TI1 DAC3484IRKDT Quad-channel, 16-bit, 1.25 gsps digital-to-analog converter Datasheet

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DAC3484
SLAS749E – MARCH 2011 – REVISED NOVEMBER 2015
DAC3484 Quad-Channel, 16-Bit, 1.25 GSPS Digital-to-Analog Converter (DAC)
1 Features
3 Description
•
The DAC3484 is a very low power, high dynamic
range,
quad-channel,
16-bit
digital-to-analog
converter (DAC) with a sample rate as high as 1.25
GSPS.
1
•
•
•
•
•
•
•
•
•
•
Very Low Power: 1.27 W at 1.25 GSPS, Full
Operating Conditions
Multi-DAC Synchronization
Selectable 2x, 4x, 8x, 16x Interpolation Filter
– Stop-Band Attenuation > 90 dBc
Flexible On-chip Complex Mixing
– Two Independent Fine Mixers with 32-Bit
NCOs
– Power Saving Coarse Mixers: ± n×Fs/8
High Performance, Low Jitter Clock Multiplying
PLL
Digital I and Q Correction
– Gain, Phase, Offset, and Group Delay
Correction
Digital Inverse Sinc Filter
Flexible 16-Bit LVDS Input Data Bus
– 8 Sample Input FIFO
– Data Pattern Checker
– Parity Check
– GC5330 Compatible
Temperature Sensor
Differential Scalable Output: 10 mA to 30 mA
Multiple Package Options: 88-Pin 9x9mm WQFN
and 196-Ball 12mmx12mm NFBGA (GREEN / PbFree)
The device includes features that simplify the design
of complex transmit architectures: 2x to 16x digital
interpolation filters with over 90dB of stop-band
attenuation simplify the data interface and
reconstruction filters. Independent complex mixers
allow flexible carrier placement. A high-performance
low jitter clock multiplier simplifies clocking of the
device without significant impact on the dynamic
range. The digital Quadrature Modulator Correction
(QMC) enables complete IQ compensation for gain,
offset, phase and group delay between channels in
direct up-conversion applications.
Digital data is input to the device through a 16-bit
LVDS data bus with on-chip termination. The device
includes a FIFO, data pattern checker and parity test
to ease the input interface. The interface also allows
full synchronization of multiple devices.
The device is characterized for operation over the
entire industrial temperature range of –40°C to 85°C
and is available in a very-small 88-pin 9x9mm WQFN
package or 196-ball 12x12mm NFBGA package.
Very low power, small size, superior crosstalk, high
dynamic range and features of the DAC3484 are an
ideal fit for systems with multiple transmit channels.
Device Information(1)
2 Applications
•
•
•
Cellular Base Stations
Diversity Transmit
Wideband Communications
PART NUMBER
DAC3484
PACKAGE
BODY SIZE (NOM)
WQFN (88)
9.00 mm x 9.00 mm
NFBGA (196)
12.00 mm x 12.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
16-bit DAC
RF
16-bit DAC
xN
xN
Complex Mixer
(32-bit NCO)
LVDS Interface
16-Bit LVDS Input Data Bus
xN
Complex Mixer
(32-bit NCO)
DAC3484
16-bit DAC
RF
16-bit DAC
xN
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
DAC3484
SLAS749E – MARCH 2011 – REVISED NOVEMBER 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
Features .................................................................. 1
Applications ........................................................... 1
Description ............................................................. 1
Revision History..................................................... 2
Pin Configuration and Functions ......................... 5
Specifications....................................................... 11
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
7
Absolute Maximum Ratings ....................................
ESD Ratings ..........................................................
Recommended Operating Conditions.....................
Thermal Information ................................................
Electrical Characteristics – DC Specifications ........
Electrical Characteristics – Digital Specifications ...
Electrical Characteristics – AC Specifications ........
Timing Requirements – Digital Specifications.........
Switching Characteristics – AC Specifications........
Typical Characteristics ..........................................
11
11
11
12
12
14
15
15
17
18
Detailed Description ............................................ 27
7.1 Overview ................................................................. 27
7.2 Functional Block Diagram ....................................... 28
7.3
7.4
7.5
7.6
8
Feature Description.................................................
Device Functional Modes........................................
Programming...........................................................
Register Map...........................................................
29
58
62
66
Application and Implementation ........................ 83
8.1 Application Information............................................ 83
8.2 Typical Applications ............................................... 84
9 Power Supply Recommendations...................... 90
10 Layout................................................................... 91
10.1 Layout Guidelines ................................................. 91
10.2 Layout Examples................................................... 92
11 Device and Documentation Support ................. 95
11.1
11.2
11.3
11.4
11.5
11.6
Device Support......................................................
Documentation Support ........................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
95
96
96
96
96
96
12 Mechanical, Packaging, and Orderable
Information ........................................................... 96
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision D (September 2015) to Revision E
•
Page
Changed I(CLKVDD) Clock supply current Mode 1 max value from 95mA to 100mA .............................................................. 13
Changes from Revision C (August 2012) to Revision D
Page
•
Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation
section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and
Mechanical, Packaging, and Orderable Information section. ................................................................................................ 1
•
Added 196-ball 12x12mm BGA package to Description ........................................................................................................ 1
•
Added additional operation requirement for SLEEP pin if SLEEP pin is set to logic HIGH before and during device
power up and initialization. ..................................................................................................................................................... 7
•
Added additional circuit configuration for unused terminals - IOUTAP/N, IOUTBP/N, IOUTCP/N, IOUTDP/N ..................... 9
•
Added additional operation requirement for SLEEP pin if SLEEP pin is set to logic HIGH before and during device
power up and initialization. ................................................................................................................................................... 10
•
Changed DACCLKP/N Differential voltage TYP value from 1.0 V to 0.8 V ........................................................................ 14
•
Changed the parameter name Single-Ended Swing Level to Single-Ended Input Level to better reflect the
specification for minimum recommended single-ended voltage level. ................................................................................ 14
•
Changed OSTRP/N Differential voltage TYP value from 1.0 V to 0.8 V ............................................................................. 14
•
Changed the parameter name Single-Ended Swing Level to Single-Ended Input Level to better reflect the
specification for minimum recommended single-ended voltage level. ................................................................................ 14
•
Changed Standard high swing note for Electrical Characteristics – Digital Specifications .................................................. 14
•
Added Minimum voltage note for Electrical Characteristics – Digital Specifications ........................................................... 14
•
Added LMK0480x family to note for Timing Requirements – Digital Specifications ........................................................... 16
•
Added text to Input FIFO section ......................................................................................................................................... 32
•
Changed syncsel_fifoout(3:0) description in Input FIFO section to clarify the FIFO read pointer reset capture method
and limitation......................................................................................................................................................................... 33
2
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SLAS749E – MARCH 2011 – REVISED NOVEMBER 2015
•
Added Note to Input FIFO section ....................................................................................................................................... 33
•
Added LMK0480x family to Input FIFO section ................................................................................................................... 33
•
Changed text in Single Sync Source Mode to clarify the latency limitation of Single Sync Source Mode........................... 35
•
Added the effect of bypassing the FIFO in the Bypass Mode section to clarify the operation of the FIFO, LVDS
FRAME, and LVDS SYNC in FIFO Bypass Mode. ............................................................................................................. 35
•
Added package information for LPF pin in PLL Mode section ............................................................................................. 37
•
Changed table reference in FIR Filters section ................................................................................................................... 38
•
Added text to Data Pattern Checker section with additional operating recommendations. ................................................ 49
•
Added reference to application report in DAC3484 Alarm Monitoring section ..................................................................... 53
•
Added note to Figure 80 ...................................................................................................................................................... 54
•
Added Unused LVDS Port Termination section ................................................................................................................... 55
•
Changed information to Multi-Device Operation: Single Sync Source mode section to clarify the latency limitation of
Single Sync Source Mode. ................................................................................................................................................... 61
•
Changed Figure 90 to clarify the latency limitation of Single Sync Source Mode. .............................................................. 62
•
Changed the NCO setting description in the Example Start-up Sequence Section to reflect the example register writes. 64
•
Added A32 to A32 for DAC3484IRKD and N9 for DAC3484IZAY in register config3 bit 0 description ............................... 70
•
Changed alarm_lparity to alarm_fparity in register config7 ................................................................................................. 72
•
Changed QMC offset registers to QMC correction registers in register config16 ................................................................ 74
•
Added SLEEP pin information to register config27 bit 11 ................................................................................................... 77
•
Changed 1.2VDIG to DIGVDD in register config27 bits 5:0................................................................................................. 77
•
Changed 1.2VCLK to CLKVDD in register config27 bits 5:0................................................................................................ 77
•
Added pin description for both packages in register config35 ............................................................................................. 80
•
Added reference to Digital Input Timing Specifications Table in register config36 .............................................................. 80
•
Added text to register config45 bit 0 description .................................................................................................................. 81
Changes from Revision B (February) to Revision C
Page
•
Deleted TJ row from top of thermal table................................................................................................................................ 2
•
Added thermal information to the Absolute Maximum Ratings table ................................................................................... 11
•
Added Recommended Operating Conditions table .............................................................................................................. 11
•
Deleted TJ row from top of thermal table.............................................................................................................................. 12
•
Deleted OPERATING RANGE section from bottom of Electrical Characteristics – DC Specifications table ...................... 13
Changes from Revision A (July 2011) to Revision B
Page
•
Changed the revision from A, July 2011 to B, June 2012...................................................................................................... 1
•
Changed Package options in FEATURES ............................................................................................................................. 1
•
Added ZAY package information to Thermal Information ...................................................................................................... 2
•
Added ZAY package............................................................................................................................................................... 8
•
Added ZAY pin functions ........................................................................................................................................................ 9
•
Added ZAY package information to Thermal Information .................................................................................................... 12
•
Added Input Common Mode max value of 1.6V .................................................................................................................. 14
•
Added information to CLOCK INPUT (DACCLKP/N) in Electrical Characteristics – Digital Specifications ......................... 14
•
Added information to OUTPUT STROBE (OSTRP/N) in Electrical Characteristics – Digital Specifications ....................... 14
•
Changed Electrical Characteristics – AC Specifications AC Performance information........................................................ 15
•
Changed Figure 21............................................................................................................................................................... 20
•
Changed Figure 22............................................................................................................................................................... 20
•
Changed Figure 23............................................................................................................................................................... 20
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SLAS749E – MARCH 2011 – REVISED NOVEMBER 2015
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•
Added Figure 48 ................................................................................................................................................................... 24
•
Added Figure 49 ................................................................................................................................................................... 25
•
Changed config 3 to config9 in Input FIFO section .............................................................................................................. 32
•
Added information for double-charge-pump current to PLL MODE section......................................................................... 37
•
Changed Figure 71............................................................................................................................................................... 43
•
Changed +3.75 to –3.75 degrees in 1024 steps to +26.5 to –26.5 degrees in 4096 steps in GAIN AND PHASE
CORRECTION section ......................................................................................................................................................... 45
•
Added dual channel mode enable information to POWER-UP SEQUENCE step 6. ........................................................... 62
•
Changed config1, bit 8 in Table 11....................................................................................................................................... 66
•
Changed config16, bits 13:12 in Table 11............................................................................................................................ 66
•
Changed register config1, bit8 from Reserved to quad_ena................................................................................................ 69
•
Changed register config16, bits 13:12 from reserved to dual_ena (1:0) .............................................................................. 74
Changes from Original (March 2011) to Revision A
•
4
Page
Changed from PRODUCT PREVIEW to PRODUCTION DATA ............................................................................................ 1
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SLAS749E – MARCH 2011 – REVISED NOVEMBER 2015
5 Pin Configuration and Functions
LPF
PLLAVDD
OSTRP
OSTRN
DACCLKP
DACCLKN
CLKVDD
VFUSE
SYNCP
SYNCN
DIGVDD
IOVDD
D15P
D15N
D14P
D14N
DIGVDD
D13P
D13N
D12P
D12N
A44
B40
A43
B39
A42
B38
A41
B37
A40
B36
A39
B35
A38
B34
A37
C1
A1
IOUTDN
AVDD
IOUTDP
DACVDD
AVDD
EXTIO
C4
B33
A36
B32
A35
B31
A34
TESTMODE
SLEEP
DACVDD
IOUTAP
AVDD
IOUTAN
AVDD
IOUTBN
AVDD
IOUTBP
DACVDD
IOUTCP
AVDD
IOUTCN
AVDD
RKD Package
88-Pin WQFN
Top View
B1
A2
B2
A3
B3
A4
B4
A5
B5
DAC3484
B6
88-WQFN 9mm x 9mm
A6
A7
B7
A8
B8
A9
A12
B11
A13
B12
A14
B13
A15
B14
A16
B15
A17
B16
A18
B17
A19
B18
A20
B19
A21
B20
A22
B9
A10
B10
A11
A33
B30
A32
B29
A31
B28
A30
B27
A29
B26
A28
B25
A27
B24
A26
B23
A25
B22
A24
B21
A23
BIASJ
RESETB
TXENABLE
ALARM
SCLK
SDENB
SDIO
SDO
PARITYN
PARITYP
DIGVDD
IOVDD
D0N
D0P
D1N
D1P
DIGVDD
D2N
D2P
D3N
D3P
C3
D11P
D11N
D10P
D10N
D9P
D9N
D8P
D8N
DATACLKP
DATACLKN
IOVDD
FRAMEP
FRAMEN
D7P
D7N
D6P
D6N
D5P
D5N
D4P
D4N
C2
P0133-02
Pin Functions - WQFN
PIN
I/O
DESCRIPTION
NAME
NO.
AVDD
A36, A37,
A38, A40,
A41, A42,
B31
I
Analog supply voltage. (3.3 V)
ALARM
B29
O
CMOS output for ALARM condition. The ALARM output functionality is defined through the config7
register. Default polarity is active high, but can be changed to active low via config0 alarm_out_pol
control bit.
BIASJ
A33
O
Full-scale output current bias. For 30-mA full-scale output current, connect 1.28 kΩ to ground.
Change the full-scale output current through coarse_dac(3:0) in config3, bit<15:12>
CLKVDD
A4
I
Internal clock buffer supply voltage. (1.2 V)
It is recommended to isolate this supply from DIGVDD and DACVDD.
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Pin Functions - WQFN (continued)
PIN
NAME
NO.
I/O
DESCRIPTION
A7, A8, B9,
B10, A12,
A13, A14,
A15, B17,
B18, B19,
B20, A23,
A24, B23,
B24
I
D[15..0]N
B7, B8, A10,
A11, B11,
B12, B13,
B14, A19,
A20, A21,
A22, B21,
B22, A26,
A27
I
LVDS negative input data bits 0 through 15. (See D[15:0]P description above)
DACCLKP
A3
I
Positive external LVPECL clock input for DAC core with a self-bias.
DACCLKN
B3
I
Complementary external LVPECL clock input for DAC core. (see the DACCLKP description)
DACVDD
A35, A39,
A43
I
DAC core supply voltage. (1.2 V). It is recommended to isolate this supply from CLKVDD and
DIGVDD.
A16
I
LVDS positive input data clock. Internal 100 Ω termination resistor. Input data D[15:0]P/N is latched
on both edges of DATACLKP/N (Double Data Rate).
D[15..0]P
DATACLKP
DATACLKN
DIGVDD
EXTIO
LVDS positive input data bits 0 through 15. Internal 100-Ω termination resistor. Data format relative to
DATACLKP/N clock is Double Data Rate (DDR).
D15P is most significant data bit (MSB)
D0P is least significant data bit (LSB)
The order of the bus can be reversed via config2 revbus bit.
B15
I
LVDS negative input data clock. (See DATACLKP description)
A6, A9, A25,
A28
I
Digital supply voltage. (1.2 V). It is recommended to isolate this supply from CLKVDD and DACVDD.
A34
I/O
Used as external reference input when internal reference is disabled through config27 extref_ena =
1b. Used as internal reference output when config27 extref_ena = 0b (default). Requires a 0.1-µF
decoupling capacitor to AGND when used as reference output.
FRAMEP
B16
I
LVDS frame indicator positive input. Internal 100-Ω termination resistor.
The main functions of this input are to reset the FIFO pointer or to be used as a syncing source.
These two functions are captured with the rising edge of DATACLKP/N. The signal captured by the
falling edge of DATACLKP/N can be used as a block parity bit. The FRAMEP/N signal should be
edge-aligned with D[15:0]P/N.
Additionally it is used to indicate the beginning of the frame.
FRAMEN
A18
I
LVDS frame indicator negative input. (See the FRAMEP description)
C1, C2, C3,
C4, Thermal
Pad
I
These pins are ground for all supplies.
IOUTAP
B39
O
A-Channel DAC current output. Connect directly to ground if unused.
IOUTAN
B38
O
A-Channel DAC complementary current output. Connect directly to ground if unused.
IOUTBP
B36
O
B-Channel DAC current output. Connect directly to ground if unused.
IOUTBN
B37
O
B-Channel DAC complementary current output. Connect directly to ground if unused.
IOUTCP
B35
O
C-Channel DAC current output. Connect directly to ground if unused.
IOUTCN
B34
O
C-Channel DAC complementary current output. Connect directly to ground if unused.
IOUTDP
B32
O
D-Channel DAC current output. Connect directly to ground if unused.
GND
IOUTDN
B33
O
D-Channel DAC complementary current output. Connect directly to ground if unused.
B6, A17, B25
I
Supply voltage for all digital I/O. (3.3 V)
LPF
A1
I/O
OSTRP
A2
I
LVPECL output strobe positive input. This positive/negative pair is captured with the rising edge of
DACCLKP/N. It is used for multiple DAC synchronization. If unused it can be left unconnected.
OSTRN
B2
I
LVPECL output strobe negative input. (See the OSTRP description)
PARITYP
B26
I
Optional LVDS positive input parity bit. The PARITYP/N LVDS pair has an internal 100 Ω termination
resistor. If unused it can be left unconnected.
PARITYN
A29
I
Optional LVDS negative input parity bit.
PLLAVDD
B1
I
PLL analog supply voltage. (3.3 V)
IOVDD
6
PLL loop filter connection. If not using the clock multiplying PLL, the LPF pin can be left unconnected.
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Pin Functions - WQFN (continued)
PIN
I/O
DESCRIPTION
NAME
NO.
SCLK
A31
I
Serial interface clock. Internal pull-down.
SDENB
B28
I
Active low serial data enable, always an input to the DAC3484. Internal pull-up.
SDIO
A30
I/O
Serial interface data. Bi-directional in 3-pin mode (default) and uni-directional 4-pin mode. Internal
pull-down.
SDO
B27
O
Uni-directional serial interface data in 4-pin mode. The SDO pin is tri-stated in 3-pin interface mode
(default).
SLEEP
B40
I
Active high asynchronous hardware power-down input. Internal pull-down. If SLEEP pin is set to logic
HIGH before and during device power-up and initialization, the fuse_sleep bit in register 0x1B, bit 11
must be written after register 0x23 during device initialization register setup.
SYNCP
A5
I
Optional LVDS SYNC positive input. The SYNCP/N LVDS pair has an internal 100-Ω termination
resistor. If unused it can be left unconnected.
SYNCN
B5
I
Optional LVDS SYNC negative input.
RESETB
B30
I
Active low input for chip RESET, which resets all the programming registers to their default state.
Internal pull-up.
TXENABLE
A32
I
Transmit enable active high input. Internal pull-down.
To enable analog output data transmission, set sif_txenable in register config3 to 1b or pull CMOS
TXENABLE pin to high.
To disable analog output, set sif_txenable to 0b and pull CMOS TXENABLE pin to low. The DAC
output is forced to midscale.
TESTMODE
A44
I
This pin is used for factory testing. Internal pull-down. Leave unconnected for normal operation.
VFUSE
B4
I
Digital supply voltage. This supply pin is also used for factory fuse programming. Connect to
DACVDD for normal operation.
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ZAY Package
196-Pin NFBGA
Top View
A
B
C
D
E
F
G
H
J
K
L
M
N
P
14
GND
IOUT
AP
IOUT
AN
GND
IOUT
BN
IOUT
BP
GND
GND
IOUT
CP
IOUT
CN
GND
IOUT
DN
IOUT
DP
GND
13
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
12
DAC
CLKP
GND
CLK
VDD
LPF
GND
GND
EXTIO
BIASJ
GND
N/C
N/C
GND
ALARM
SDO
11
DAC
CLKN
GND
PLL
AVDD
PLL
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
N/C
GND
N/C
SDIO
10
GND
GND
GND
AVDD
DAC
VDD
DAC
VDD
DAC
VDD
DAC
VDD
DAC
VDD
DAC
VDD
AVDD
GND
RESET
SDENB
B
9
OS
TRP
OS
TRN
GND
DAC
VDD
DAC
VDD
GND
GND
GND
GND
DAC
VDD
DAC
VDD
GND
TX
SCLK
ENABLE
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
N/C
N/C
8
TEST SLEEP
MODE
7
N/C
N/C
GND
VFUSE
DIG
VDD
GND
GND
GND
GND
DIG
VDD
N/C
GND
N/C
N/C
6
N/C
N/C
GND
IO
VDD
DIG
VDD
GND
GND
GND
GND
DIG
VDD
IO
VDD
GND
N/C
N/C
GND
IO
VDD
DIG
VDD
DIG
VDD
IO
VDD
IO
VDD
DIG
VDD
DIG
VDD
IO
VDD
GND
5
SYNCP SYNCN
PARITY PARITY
P
N
4
D15P
D15N
N/C
N/C
N/C
N/C
N/C
N/C
N/C
N/C
N/C
N/C
D0P
D0N
3
D14P
D14N
N/C
N/C
N/C
N/C
N/C
N/C
N/C
N/C
N/C
N/C
D1P
D1N
2
D13P
D13N
D11P
D10P
D9P
D8P
DATA FRAME
CLKP
P
D7P
D6P
D5P
D4P
D2P
D2N
1
D12P
D12N
D11N
D10N
D9N
D8N
DATA FRAME
CLKN
N
D7N
D6N
D5N
D4N
D3P
D3N
DAC Output
Data Input
3.3V Supply
Clock Input
CMOS Pins
1.2V Supply
(except for IOVDD2)
Sync/Parity Input
N/C
Ground
P0134-02
8
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Pin Functions - NFBGA
PIN
I/O
DESCRIPTION
NAME
NO.
AVDD
D10, E11, F11, G11,
H11, J11, K11, L10
I
Analog supply voltage. (3.3 V)
ALARM
N12
O
CMOS output for ALARM condition. The ALARM output functionality is defined through the
config7 register. Default polarity is active low, but can be changed to active high via
config0 alarm_out_pol control bit.
BIASJ
H12
O
Full-scale output current bias. For 30-mA full-scale output current, connect 1.28 kΩ to
ground. Change the full-scale output current through coarse_dac(3:0) in config3,
bit<15:12>
CLKVDD
C12
I
Internal clock buffer supply voltage. (1.2 V)
It is recommended to isolate this supply from DIGVDD and DACVDD.
D[15..0]P
N4, N3, N2, N1, M2, L2,
K2, J2, F2, E2, D2, C2,
A1, A2, A3, A4
LVDS positive input data bits 0 through 15. Internal 100-Ω termination resistor. Data
format relative to DATACLKP/N clock is Double Data Rate (DDR).
I
D15P is most significant data bit (MSB)
D0P is least significant data bit (LSB)
The order of the bus can be reversed via config2 revbus bit.
D[15..0]N
P4, P3, P2, P1, M1, L1,
K1, J1, F1, E1, D1, C1,
B1, B2, B3, B4
I
LVDS negative input data bits 0 through 15. (See D[15:0]P description above)
DACCLKP
A12
I
Positive external LVPECL clock input for DAC core with a self-bias.
DACCLKN
A11
I
Complementary external LVPECL clock input for DAC core. (see the DACCLKP
description)
DACVDD
D9, E9, E10, F10, G10,
H10, J10, K9, K10, L9
I
DAC core supply voltage. (1.2 V). It is recommended to isolate this supply from CLKVDD
and DIGVDD.
DATACLKP
G2
I
LVDS positive input data clock. Internal 100-Ω termination resistor. Input data D[15:0]P/N
is latched on both edges of DATACLKP/N (Double Data Rate).
DATACLKN
G1
I
LVDS negative input data clock. (See DATACLKP description)
E5, E6, E7, F5, J5, K5,
K6, K7
I
Digital supply voltage. (1.2 V). It is recommended to isolate this supply from CLKVDD and
DACVDD.
DIGVDD
EXTIO
G12
I/O
Used as external reference input when internal reference is disabled through config27
extref_ena = 1b. Used as internal reference output when config27 extref_ena = 0b
(default). Requires a 0.1-µF decoupling capacitor to AGND when used as reference
output.
FRAMEP
H2
I
LVDS frame indicator positive input. Internal 100-Ω termination resistor.
The main functions of this input are to reset the FIFO pointer or to be used as a syncing
source. These two functions are captured with the rising edge of DATACLKP/N. The signal
captured by the falling edge of DATACLKP/N can be used as a block parity bit. The
FRAMEP/N signal should be edge-aligned with D[15:0]P/N.
Additionally it is used to indicate the beginning of the frame.
FRAMEN
H1
I
LVDS frame indicator negative input. (See the FRAMEP description)
A10, A13, A14, B10,
B11, B12, B13, C5, C6,
C7, C8, C9, C10, C13,
D8, D13, D14, E8, E12,
E13, F6, F7, F8, F9,
F12, F13, G6, G7, G8,
G9, G13, G14, H6, H7,
H8, H9, H13, H14, J6,
J7, J8, J9, J12, J13, K8,
K13, L8, L13, L14, M5,
M6, M7, M8, M9, M10,
M11, M12, M13, N13,
P13, P14
I
These pins are ground for all supplies.
IOUTAP
B14
O
A-Channel DAC current output. Connect directly to ground if unused.
IOUTAN
C14
O
A-Channel DAC complementary current output. Connect directly to ground if unused.
IOUTBP
F14
O
B-Channel DAC current output. Connect directly to ground if unused.
IOUTBN
E14
O
B-Channel DAC complementary current output. Connect directly to ground if unused.
IOUTCP
J14
O
C-Channel DAC current output. Connect directly to ground if unused.
GND
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Pin Functions - NFBGA (continued)
PIN
NAME
NO.
I/O
DESCRIPTION
IOUTCN
K14
O
C-Channel DAC complementary current output. Connect directly to ground if unused.
IOUTDP
N14
O
D-Channel DAC current output. Connect directly to ground if unused.
IOUTDN
M14
O
D-Channel DAC complementary current output. Connect directly to ground if unused.
D5, D6, G5, H5, L5, L6
I
Supply voltage for all digital I/O. (3.3 V)
D12
I
PLL loop filter connection. If not using the clock multiplying PLL, the LPF pin can be left
unconnected.
OSTRP
A9
I
LVPECL output strobe positive input. This positive/negative pair is captured with the rising
edge of DACCLKP/N. It is used for multiple DAC synchronization. If unused it can be left
unconnected.
OSTRN
B9
I
LVPECL output strobe negative input. (See the OSTRP description)
PARITYP
N5
I
Optional LVDS positive input parity bit. The PARITYP/N LVDS pair has an internal 100-Ω
termination resistor. If unused it can be left unconnected.
PARITYN
P5
I
Optional LVDS negative input parity bit.
PLLAVDD
C11, D11
I
PLL analog supply voltage. (3.3 V)
SCLK
P9
I
Serial interface clock. Internal pull-down.
SDENB
P10
I
Active low serial data enable, always an input to the DAC3484. Internal pull-up.
SDIO
P11
I/O
Serial interface data. Bi-directional in 3-pin mode (default) and 4-pin mode. Internal pulldown.
SDO
P12
O
Uni-directional serial interface data in 4-pin mode. The SDO pin is three-stated in 3-pin
interface mode (default).
IOVDD
LPF
SLEEP
B8
I
Active high asynchronous hardware power-down input. Internal pull-down. If SLEEP pin is
set to logic HIGH before and during device power-up and initialization, the fuse_sleep bit
in register 0x1B, bit 11 must be written after register 0x23 during device initialization
register setup.
SYNCP
A5
I
Optional LVDS SYNC positive input. The SYNCP/N LVDS pair has an internal 100-Ω
termination resistor. If unused it can be left unconnected.
SYNCN
B5
I
LVDS SYNC negative input.
RESETB
N10
I
Active low input for chip RESET, which resets all the programming registers to their default
state. Internal pull-up.
TXENABLE
N9
I
Transmit enable active high input. Internal pull-down.
To enable analog output data transmission, set sif_txenable in register config3 to 1b or
pull CMOS TXENABLE pin to high.
To disable analog output, set sif_txenable to 0b and pull CMOS TXENABLE pin to low.
The DAC output is forced to midscale.
TESTMODE
A8
O
This pin is used for factory testing. Internal pull-down. Leave unconnected for normal
operation.
VFUSE
D7
I
Digital supply voltage. This supply pin is also used for factory fuse programming. Connect
to DACVDD for normal operation.
10
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
MAX
UNIT
DACVDD, DIGVDD, CLKVDD
–0.5
1.5
V
VFUSE
–0.5
1.5
V
IOVDD
–0.5
4
V
AVDD, PLLAVDD
–0.5
4
V
D[15..0]P/N, DATACLKP/N, FRAMEP/N, PARITYP/N, SYNCP/N
–0.5
IOVDD + 0.5
V
DACCLKP/N, OSTRP/N
–0.5
CLKVDD + 0.5
V
ALARM, SDO, SDIO, SCLK, SDENB, SLEEP, RESETB, TESTMODE,
TXENABLE
–0.5
IOVDD + 0.5
V
IOUTAP/N, IOUTBP/N, IOUTCP/N, IOUTDP/N
–1.0
AVDD + 0.5
V
EXTIO, BIASJ
–0.5
AVDD + 0.5
V
LPF
0.5
PLLAVDD+0.5V
V
Peak input current (any input)
20
mA
Peak total input current (all inputs)
–30
mA
85
°C
150
°C
150
°C
Supply voltage
range (2)
Pin voltage range (2)
Operating free-air temperature range, TA: DAC3484
–40
Absolute maximum junction temperature, TJ
Storage temperature range
(1)
(2)
–65
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only and functional operation of these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Measured with respect to GND.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
±500
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
MIN
TJ
TA
(1)
NOM
Recommended operating junction temperature
MAX
105
Maximum rated operating junction temperature (1)
125
Recommended free-air temperature
–40
25
85
UNIT
°C
°C
Prolonged use at this junction temperature may increase the device failure-in-time (FIT) rate.
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6.4 Thermal Information
DAC3484
THERMAL METRIC
(1)
RKD
(WQFN-MR)
ZAY
(NFBGA)
88 PINS
196 BALLS
UNIT
RθJA
Junction-to-ambient thermal resistance
22.1
37.6
°C/W
RθJCtop
Junction-to-case (top) thermal resistance
7.1
6.8
°C/W
RθJCbot
Junction-to-case (bottom) thermal resistance
0.6
N/A
°C/W
θJB
Junction-to-board thermal resistance
4.7
16.8
°C/W
ψJT
Junction-to-top characterization parameter
0.1
0.2
°C/W
ψJB
Junction-to-board characterization parameter
4.6
16.4
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report (SPRA953).
6.5 Electrical Characteristics – DC Specifications (1)
over recommended operating free-air temperature range, nominal supplies, IOUTFS = 20 mA (unless otherwise noted)
PARAMETER
TEST CONDITIONS
Resolution
MIN
TYP MAX
16
UNIT
Bits
DC ACCURACY
DNL
Differential nonlinearity
INL
Integral nonlinearity
1 LSB = IOUTFS/216
±2
LSB
±4
LSB
ANALOG OUTPUT
Coarse gain linearity
Offset error
Gain error
Gain mismatch
±0.04
LSB
±0.001
%FSR
With external reference
±2
%FSR
With internal reference
±2
%FSR
With internal reference
±2
%FSR
Mid code offset
Full scale output current
10
Output compliance range
20
–0.5
Output resistance
Output capacitance
30
0.6
mA
V
300
kΩ
5
pF
REFERENCE OUTPUT
VREF
Reference output voltage
1.2
V
Reference output current (2)
100
nA
REFERENCE INPUT
VEXTIO
Input voltage range
Input resistance
External Reference Mode
0.6
1.2
1.25
V
1
MΩ
Small signal bandwidth
472
kHz
Input capacitance
100
pF
±1
ppm/°C
with external reference
±15
ppm/°C
with internal reference
±30
ppm/°C
±8
ppm/°C
TEMPERATURE COEFFICIENTS
Offset drift
Gain drift
Reference voltage drift
(1)
(2)
12
Measured differentially across IOUTP/N with 25 Ω each to GND.
Use an external buffer amplifier with high impedance input to drive any external load.
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Electrical Characteristics – DC Specifications(1) (continued)
over recommended operating free-air temperature range, nominal supplies, IOUTFS = 20 mA (unless otherwise noted)
PARAMETER
POWER SUPPLY
PSRR
TEST CONDITIONS
MIN
TYP MAX
UNIT
(3)
AVDD, IOVDD, PLLAVDD
All Conditions
3.14
3.3
3.46
V
DIGVDD
All Conditions
1.14
1.2
1.32
V
CLKVDD, DACVDD
FDAC Sampling Rate ≤ 1.25 GSPS, PLL OFF
FDAC Sampling Rate ≤ 1 GSPS, PLL ON
1.14
1.2
1.32
FDAC Sampling Rate > 1 GSPS, PLL ON
1.25
1.29
1.32
Power Supply Rejection Ratio
DC tested
±0.2
V
%FSR/V
POWER CONSUMPTION
I(AVDD)
Analog supply current (4)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
I(AVDD)
Analog supply current (4)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
I(AVDD)
Analog supply current (4)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
I(AVDD)
Analog supply current (4)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
I(AVDD)
Analog supply current (4)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power Dissipation
I(AVDD)
Analog supply current(4)
MODE 1
fDAC = 1.25 GSPS, 4x interpolation, Mixer on,
QMC on, invsinc on, PLL enabled, 20-mA FS
output, IF = 200 MHz
MODE 2
fDAC = 1.25 GSPS, 4x interpolation, Mixer on,
QMC on, invsinc on, PLL disabled, 20-mA FS
output, IF = 200 MHz
MODE 3
fDAC = 625 MSPS, 2x interpolation, Mixer on,
QMC on, invsinc off, PLL disabled, 20-mA FS
output, IF = 200 MHz
MODE 4
fDAC = 1.25 GSPS, 4x interpolation, Mixer on,
QMC on, invsinc on, PLL enabled, Channels
A/B/C/D output sleep, IF = 200 MHz,
Mode 5
Power-Down mode: No clock,
DAC on sleep mode (clock receiver sleep),
Channels A/B/C/D output sleep, static data
pattern
Mode 6
fDAC = 1 GSPS, 8x interpolation, Mixer off,
QMC on, invsinc off, PLL enabled, 20-mA FS
output, IF = 200 MHz
123
135
mA
595
650
mA
35
50
mA
90
100
mA
1270 1320
mW
107
mA
595
mA
38
mA
71
mA
1198
mW
107
mA
282
mA
20
mA
41
mA
765
mW
35
mA
595
mA
38
mA
90
mA
984
mW
20
mA
10
mA
4
mA
10
mA
95
mW
107
mA
333
mA
35
mA
60
mA
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
867
mW
I(AVDD)
Analog supply current(4)
123
mA
I(DIGVDD)
Digital supply current
323
mA
I(DACVDD)
DAC supply current
23
mA
I(CLKVDD)
Clock supply current
P
Power dissipation
(3)
(4)
Mode 7
fDAC = 737.28 MSPS, 4x interpolation, Mixer on,
QMC on, invsinc off, PLL enabled, 20-mA FS
output, IF = 150 MHz
69
mA
904
mW
To ensure power supply accuracy and to account for power supply filter network loss at operating conditions, the use of the ATEST
function in register config27 to check the internal power supply nodes is recommended.
Includes AVDD, PLLAVDD, and IOVDD
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6.6 Electrical Characteristics – Digital Specifications
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
LVDS INPUTS: D[15:0]P/N, DATACLKP/N, FRAMEP/N, SYNCP/N, PARITYP/N (1)
VA,B+
Logic high differential input
voltage threshold
VA,B–
Logic low differential input
voltage threshold
VCOM
Input Common Mode
1.0
1.2
1.6
V
ZT
Internal termination
85
110
135
Ω
CL
LVDS Input capacitance
fINTERL
Interleaved LVDS data
transfer rate
1250
MSPS
fDATA
Input data rate
312.5
MSPS
200
mV
–200
2
mV
pF
CLOCK INPUT (DACCLKP/N)
Differential voltage (2)
|DACCLKP - DACCLKN|
0.4
Internally biased commonmode voltage
Single-ended input level
(3)
0.8
V
0.2
V
–0.4
V
OUTPUT STROBE (OSTRP/N)
Differential voltage
|OSTRP – OSTRN|
0.4
Internally biased commonmode voltage
Single-ended input level
(3)
0.8
V
0.2
V
–0.4
V
CMOS INTERFACE: ALARM, SDO, SDIO, SCLK, SDENB, SLEEP, RESETB, TXENABLE
VIH
High-level input voltage
VIL
Low-level input voltage
IIH
High-level input current
-40
IIL
Low-level input current
-40
CI
CMOS Input capacitance
VOH
ALARM, SDO, SDIO
2
(1)
(2)
(3)
14
ALARM, SDO, SDIO
V
40
µA
40
µA
2
pF
IOVDD –
0.2
Iload = –100 μA
Iload = –2 mA
VOL
V
0.8
V
0.8 x IOVDD
V
Iload = 100 μA
0.2
V
Iload = 2 mA
0.5
V
See LVDS Inputs section for terminology.
Standard high swing LVPECL clock signal should be applied for best performance.
Indicates the minimum voltage that can be applied to the DACCLK and OSTR differential pins in single-ended fashion.
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6.7 Electrical Characteristics – AC Specifications
over recommended operating free-air temperature range, nominal supplies, IOUTFS = 20mA (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
ANALOG OUTPUT (1)
fDAC
Maximum DAC rate
1250
MSPS
AC PERFORMANCE (2)
Spurious free dynamic range
(0 to fDAC/2) Tone at 0 dBFS
SFDR
Third-order two-tone intermodulation distortion
Each tone at –12 dBFS
IMD3
Noise Spectral Density
Tone at 0dBFS
NSD
Adjacent channel leakage ratio, single carrier
ACLR
(3)
Alternate channel leakage ratio, single carrier
Channel Isolation
(1)
(2)
(3)
fDAC = 1.25 GSPS, fOUT = 20 MHz
82
fDAC = 1.25 GSPS, fOUT = 50 MHz
77
fDAC = 1.25 GSPS, fOUT = 70 MHz
72
fDAC = 1.25 MSPS, fOUT = 30 ± 0.5 MHz
81
fDAC = 1.25 GSPS, fOUT = 50 ± 0.5 MHz
dBc
79
fDAC = 1.25 GSPS, fOUT = 100 ± 0.5 MHz
77.5
fDAC = 1.25 GSPS, fOUT = 10 MHz
160
fDAC = 1.25 GSPS, fOUT = 80 MHz
155
fDAC = 1.2288 GSPS, fOUT = 30.72 MHz
77
fDAC = 1.2288 GSPS, fOUT = 153.6 MHz
74
fDAC = 1.2288 GSPS, fOUT = 30.72 MHz
82
fDAC = 1.2288 GSPS, fOUT = 153.6 MHz
80
fDAC = 1.25 GSPS, fOUT = 10 MHz
84
dBc
dBc/Hz
dBc
dBc
Measured single ended into 50-Ω load.
4:1 transformer output termination, 50 Ω doubly terminated load.
Single carrier, W-CDMA with 3.84-MHz BW, 5-MHz spacing, centered at IF, PAR = 12dB. TESTMODEL 1, 10 ms
6.8 Timing Requirements – Digital Specifications
MIN
NOM
MAX
UNIT
CLOCK INPUT (DACCLKP/N)
Duty cycle
40%
60%
DACCLKP/N input frequency
1250
MHz
fDACCLK /
(8 x interp)
MHz
OUTPUT STROBE (OSTRP/N)
fOSTR
Frequency
fOSTR = fDACCLK / (n x 8 x Interp) where n is any positive
integer, fDACCLK is DACCLK frequency in MHz
Duty cycle
50%
DIGITAL INPUT TIMING SPECIFICATIONS
Timing LVDS inputs: D[15:0]P/N, FRAMEP/N, SYNCP/N, PARITYP/N, double edge latching
Config36 Setting
ts(DATA)
Setup time,
D[15:0]P/N,
FRAMEP/N,
SYNCP/N and
PARITYP/N, valid
to either edge of
DATACLKP/N
FRAMEP/N reset and frame indicator
latched on rising edge of
DATACLKP/N.
FRAMEP/N parity bit latched on falling
edge of DATACLKP/N.
datadly
clkdly
0
0
150
0
1
100
0
2
50
0
3
0
0
4
-50
0
5
-100
0
6
-150
0
7
-200
1
0
200
2
0
250
3
0
300
4
0
350
5
0
400
6
0
450
7
0
500
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Timing Requirements – Digital Specifications (continued)
MIN
NOM
MAX
UNIT
Config36 Setting
Hold time,
D[15:0]P/N,
FRAMEP/N,
SYNCP/N and
PARITYP/N, valid
after either edge of
DATACLKP/N
th(DATA)
t(FRAME_SYNC)
FRAMEP/N and
SYNCP/N pulse
width
FRAMEP/N reset and frame indicator
latched on rising edge of
DATACLKP/N.
FRAMEP/N parity bit latched on falling
edge of DATACLKP/N.
datadly
clkdly
0
0
350
0
1
400
0
2
450
0
3
500
0
4
550
0
5
600
0
6
650
0
7
700
1
0
300
2
0
250
3
0
200
4
0
150
5
0
100
6
0
50
7
0
fDATACLK is DATACLK frequency in MHz
ps
0
1/2fDATACLK
ns
0
ps
300
ps
TIMING OUTPUT STROBE INPUT: DACCLKP/N rising edge LATCHING (1)
ts(OSTR)
Setup time, OSTRP/N valid to rising edge of DACCLKP/N
th(OSTR)
Hold time, OSTRP/N valid after rising edge of DACCLKP/N
TIMING SYNC INPUT: DACCLKP/N rising edge LATCHING
(2)
ts(SYNC_PLL)
Setup time, SYNCP/N valid to rising edge of DACCLKP/N
200
ps
th(SYNC_PLL)
Hold time, SYNCP/N valid after rising edge of DACCLKP/N
300
ps
TIMING SERIAL PORT
ts(SDENB)
Setup time, SDENB to rising edge of SCLK
20
ns
ts(SDIO)
Setup time, SDIO valid to rising edge of SCLK
10
ns
th(SDIO)
Hold time, SDIO valid to rising edge of SCLK
5
ns
1
µs
Register config6 read (temperature sensor read)
t(SCLK)
Period of SCLK
td(Data)
Data output delay after falling edge of SCLK
10
ns
tRESET
Minimum RESETB pulse width
25
ns
(1)
(2)
16
All other registers
100
ns
OSTR is required in Dual Sync Sources mode. In order to minimize the skew it is recommended to use the same clock distribution
device such as Texas Instruments CDCE62005 or LMK0480x family to provide the DACCLK and OSTR signals to all the DAC3484
devices in the system. Swap the polarity of the DACCLK outputs with respect to the OSTR ones to establish proper phase relationship.
SYNC is required to synchronize the PLL circuit in multiple devices. The SYNC signal must meet the timing relationship with respect to
the reference clock (DACCLKP/N) of the on-chip PLL circuit.
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6.9 Switching Characteristics – AC Specifications
over recommended operating free-air temperature range, nominal supplies, IOUTFS = 20 mA (unless otherwise noted)
PARAMETER
ANALOG OUTPUT
ts(DAC)
TEST CONDITIONS
MIN
TYP
MAX
UNIT
(1)
Output settling time to 0.1% Transition: Code 0x0000 to 0xFFFF
DAC outputs are updated on the falling edge of DAC
clock. Does not include Digital Latency (see below).
10
ns
2
ns
tpd
Output propagation delay
tr(IOUT)
Output rise time 10% to
90%
220
ps
tf(IOUT)
Output fall time 90% to
10%
220
ps
Digital latency
Power-up
Time
(1)
No interpolation, FIFO on, Mixer off, QMC off, Inverse
sinc off
128
2x Interpolation
216
4x Interpolation
376
8x Interpolation
726
16x Interpolation
1427
Fine mixer
24
QMC
32
Inverse sinc
36
DAC wake-up time
IOUT current settling to 1% of IOUTFS from output
sleep
2
DAC sleep time
IOUT current settling to less than 1% of IOUTFS in
output sleep
2
DAC
clock
cycles
µs
Measured single ended into 50-Ω load.
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6.10 Typical Characteristics
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
5
Differential Nonlinearity Error (LSB)
Integral Nonlinearity Error (LSB)
5
4
3
2
1
0
−1
−2
−3
−4
−5
0
10k
20k
30k
Code
40k
50k
4
3
2
1
0
−1
−2
−3
−4
−5
60k
0
Figure 1. Integral Nonlinearity
Second Harmonic Distortion (dBc)
SFDR (dBc)
80
70
60
50
40
0
100
200
300
400
Output Frequency (MHz)
500
50k
60k
G002
0 dBFS
−6 dBFS
−12 dBFS
80
70
60
50
40
0
100
G003
200
300
400
Output Frequency (MHz)
500
600
G004
Figure 4. Second Harmonic Distortion vs Output Frequency
Over Input Scale
100
100
0 dBFS
−6 dBFS
−12 dBFS
90
fDATA = 312.5 MSPS, 1x Interpolation
fDATA = 312.5 MSPS, 2x Interpolation
fDATA = 312.5 MSPS, 4x Interpolation
fDATA = 156.25MSPS, 8x Interpolation
fDATA = 78.125MSPS, 16x Interpolation
90
80
80
SFDR (dBc)
Third Harmonic Distortion (dBc)
40k
90
30
600
Figure 3. SFDR vs Output Frequency Over Input Scale
70
60
70
60
50
50
40
40
0
100
200
300
400
Output Frequency (MHz)
500
600
30
0
G005
Figure 5. Third Harmonic Distortion vs Output Frequency
Over Input Scale
18
30k
Code
100
0 dBFS
−6 dBFS
−12 dBFS
90
30
20k
Figure 2. Differential Nonlinearity
100
30
10k
G001
100
200
300
400
Output Frequency (MHz)
500
600
G006
Figure 6. SFDR vs Output Frequency Over Interpolation
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Typical Characteristics (continued)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
100
100
fDAC = 600 MSPS
fDAC = 800 MSPS
fDAC = 1000 MSPS
fDAC = 1250 MSPS
90
80
SFDR (dBc)
SFDR (dBc)
80
70
60
60
50
40
40
0
100
200
300
400
Output Frequency (MHz)
500
30
600
−10
150
200
250
300
Output Frequency (MHz)
350
400
G008
−10
−20
−30
−40
−50
−30
−40
−50
−60
−60
−70
−70
−80
−80
0
100
200
300
400
Frequency (MHz)
500
NCO Bypassed
QMC Bypassed
fDAC = 1250 MSPS
fOUT = 70 MHz
0
Power (dBm)
−20
−90
600
0
100
G009
Figure 9. Single Tone Spectral Plot
200
300
400
Frequency (MHz)
500
600
G010
Figure 10. Single Tone Spectral Plot
10
10
fDAC = 1250 MSPS
fOUT = 150 MHz
0
−10
−10
−20
−20
−30
−40
−50
−30
−40
−50
−60
−60
−70
−70
−80
−80
0
100
200
300
400
Frequency (MHz)
500
fDAC = 1250 MSPS
fOUT = 200 MHz
0
Power (dBm)
Power (dBm)
100
10
NCO Bypassed
QMC Bypassed
fDAC = 1250 MSPS
fOUT = 20 MHz
0
−90
50
Figure 8. SFDR vs Output Frequency Over IOUTFS
10
−90
0
G007
Figure 7. SFDR vs Output Frequency Over fDAC
Power (dBm)
70
50
30
IOUTFS = 10 mA w/ 4:1 Transformer
IOUTFS = 20 mA w/ 4:1 Transformer
IOUTFS = 30 mA w/ 2:1 Transformer
90
−90
600
10
G011
Figure 11. Single Tone Spectral Plot
110
210
310
410
Frequency (MHz)
510
610
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Figure 12. Single Tone Spectral Plot
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Typical Characteristics (continued)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
100
10
PLL Enabled w/ PFD of 78.125 MHz
fDAC = 1250 MSPS
fOUT = 200 MHz
0
−10
80
IMD3 (dBc)
−20
Power (dBm)
0 dBFS
−6 dBFS
−12 dBFS
90
−30
−40
−50
−60
70
60
50
−70
40
−80
−90
10
110
210
310
410
Frequency (MHz)
510
30
610
100
100
90
90
80
80
70
60
fDATA = 312.5 MSPS, 1x Interpolation
fDATA = 312.5 MSPS, 2x Interpolation
fDATA = 312.5 MSPS, 4x Interpolation
fDATA = 156.25 MSPS, 8x Interpolation
fDATA = 78.125 MSPS, 16x Interpolation
40
30
0
100
200
300
400
Output Frequency (MHz)
100
200
300
400
Output Frequency (MHz)
fDAC = 600 MSPS
fDAC = 800 MSPS
fDAC = 1000 MSPS
fDAC = 1250 MSPS
60
40
500
30
600
0
100
G015
200
300
400
Output Frequency (MHz)
500
600
G016
Figure 16. IMD3 vs Output Frequency Over fDAC
0
NCO Bypassed
QMC Bypassed
fDAC = 1250 MSPS
fOUT = 70 MHz
Tone Spacing = 1 MHz
−10
90
−20
80
−30
Power (dBm)
IMD3 (dBc)
G014
50
100
70
60
−40
−50
−60
−70
50
IOUTFS = 10 mA w/ 4:1 Transformer
IOUTFS = 20 mA w/ 4:1 Transformer
IOUTFS = 30 mA w/ 2:1 Transformer
40
0
50
100
150
200
250
300
Output Frequency (MHz)
−80
−90
350
400
−100
65
G017
Figure 17. IMD3 vs Output Frequency Over IOUTFS
20
600
70
Figure 15. IMD3 vs Output Frequency Over Interpolation
30
500
Figure 14. IMD3 vs Output Frequency Over Input Scale
IMD3 (dBc)
IMD3 (dBc)
Figure 13. Single Tone Spectral Plot
50
0
G013
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66
67
68
69
70
71
72
Frequency (MHz)
73
74
75
G018
Figure 18. Two Tone Spectral Plot
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Typical Characteristics (continued)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
170
0
fDAC = 1250 MSPS
fOUT = 200 MHz
Tone Spacing = 1 MHz
−10
−20
160
NSD (dBc/Hz)
Power (dBm)
−30
−40
−50
−60
−70
150
145
135
−90
−100
195 196 197 198 199 200 201 202 203 204 205
Frequency (MHz)
G019
130
Figure 19. Two Tone Spectral Plot
170
170
165
165
160
160
155
150
145
fDATA = 312.5 MSPS, 1x interpolation
fDATA = 312.5 MSPS, 2x interpolation
fDATA = 312.5 MSPS, 4x interpolation
fDATA = 156.25 MSPS, 8x interpolation
fDATA = 78.125 MSPS, 16x interpolation
140
135
0
100
200
300
400
Output Frequency (MHz)
200
300
400
Output Frequency (dB)
500
600
G020
fDAC = 600 MSPS
fDAC = 800 MSPS
fDAC = 1000 MSPS
fDAC = 1250 MSPS
150
145
140
135
500
130
600
0
100
G021
200
300
Output Frequency (MHz)
400
500
G022
Figure 22. NSD vs Output Frequency Over fDAC
170
170
Iout FS = 10 mA, 4:1 transformer
Iout FS = 20 mA, 4:1 transformer
Iout FS = 30 mA, 2:1 transformer
165
160
155
150
145
155
150
145
140
140
135
135
0
100
200
300
Output Frequency (MHz)
400
PLL Bypassed
PLL Enabled w/ PFD of 78.125 MHz
165
NSD (dBc/Hz)
160
NSD (dBc/Hz)
100
155
Figure 21. NSD vs Output Frequency Over Interpolation
130
0
Figure 20. NSD vs Output Frequency Over Input Scale
NSD (dBc/Hz)
NSD (dBc/Hz)
155
140
−80
130
0dBFS
−6dBFS
−12dBFS
165
500
130
0
G023
Figure 23. NSD vs Output Frequency Over IOUTFS
100
200
300
400
Output Frequency (MHz)
500
600
G024
Figure 24. NSD vs Output Frequency Over Clocking Options
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Typical Characteristics (continued)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
85
85
PLL Disabled
PLL Enabled
75
70
65
60
55
PLL Disabled
PLL Enabled
80
ACLR (dBc)
ACLR (dBc)
80
75
70
65
60
0
100
200
300
400
Output Frequency (MHz)
500
600
55
0
100
G025
Figure 25. Single Carrier WCDMA ACLR (Adjacent) vs
Output Frequency Over Clocking Options
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 70 MHz
200
300
400
Output Frequency (MHz)
500
600
G026
Figure 26. Single Carrier WCDMA ACLR (Alternate) vs
Output Frequency Over Clocking Options
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 120 MHz
G027
Figure 27. Single Carrier W-CDMA Test Model 1
G028
Figure 28. Single Carrier W-CDMA Test Model 1
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 70 MHz
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 200 MHz
G029
G030
Figure 29. Single Carrier W-CDMA Test Model 1
22
Figure 30. Four Carrier W-CDMA Test Model 1
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Typical Characteristics (continued)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 120 MHz
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 200 MHz
G031
Figure 31. Four Carrier W-CDMA Test Model 1
G032
Figure 32. Four Carrier W-CDMA Test Model 1
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 140 MHz
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 240 MHz
G033
G034
Figure 33. 10-MHz Single Carrier LTE Test Model 3.1
Figure 34. 10-MHz Single Carrier LTE Test Model 3.1
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 140 MHz
4x Interpolation, 0 dBFS
fDAC = 1228.8 MSPS
fOUT = 240 MHz
G035
Figure 35. 20-MHz Single Carrier LTE Test Model 3.1
G036
Figure 36. 20-MHz Single Carrier LTE Test Model 3.1
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Typical Characteristics (continued)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
1400
1400
Power Consumption (mW)
1200
1000
800
600
400
Bandbase Input = 5 MHz
NCO Disabled
QMC Disabled
CMIX Disabled
200
0
0
200
400
600
800
fDAC (MSPS)
1000
1000
800
600
400
0
1200
600
800
fDAC (MSPS)
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
500
DIGVDD Current (mA)
Power Consumption (mW)
400
1000
1200
G038
600
120
100
80
60
40
400
Bandbase Input = 5 MHz
NCO Disabled
QMC Disabled
CMIX Disabled
300
200
100
20
0
200
400
600
800
fDAC (MSPS)
1000
0
1200
0
200
400
G039
Figure 39. Power Consumption vs fDAC Over Digital
Processing Functions
600
800
fDAC (MSPS)
1000
1200
G040
Figure 40. DIGVDD Current vs fDAC Over Interpolation
600
160
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
400
300
200
Bandbase Input = 0 MHz
NCO Enabled w/ 5 MHz Mixing
QMC Enabled
100
0
200
400
NCO Enabled
QMC Enabled
140
DIGVDD Current (mA)
500
DIGVDD Current (mA)
200
Figure 38. Power Consumption vs fDAC Over Interpolation
NCO Enabled
QMC Enabled
140
600
800
fDAC (MSPS)
1000
120
100
80
60
40
20
0
1200
0
G041
Figure 41. DIGVDD Current vs fDAC Over Interpolation
24
0
G037
160
0
Bandbase Input = 0 MHz
NCO Enabled w/ 5 MHz Mixing
QMC Enabled
200
Figure 37. Power Consumption vs fDAC Over Interpolation
0
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
1200
Power Consumption (mW)
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
200
400
600
800
fDAC (MSPS)
1000
1200
G042
Figure 42. DIGVDD Current vs fDAC Over Digital Processing
Functions
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Typical Characteristics (continued)
40
100
35
90
CLKVDD Current (mA)
DACVDD Current (mA)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
30
25
20
15
10
5
0
80
70
60
50
40
30
20
10
0
200
400
600
800
fDAC (MSPS)
1000
0
1200
0
200
140
110
120
100
100
80
60
40
20
200
400
600
800
fDAC (MSPS)
1000
G044
80
70
60
50
Channel A/B Off
Channel C/D Active
0
100
G045
200
300
400
Output Frequency (MHz)
500
600
G046
Figure 46. Channel Isolation vs Output Frequency
110
100
Channel C
Channel D
100
BGA
MrQFN
90
90
80
SFDR (dBc)
Interference Level (dBc)
1200
90
30
1200
Figure 45. AVDD Current vs fDAC
80
70
60
70
60
50
50
40
Channel C/D Off
Channel A/B Active
40
30
1000
Channel A
Channel B
40
0
600
800
fDAC (MSPS)
Figure 44. CLKVDD Current vs fDAC
Interference Level (dBc)
AVDD Current (mA)
Figure 43. DACVDD Current vs fDAC
0
400
G043
0
100
200
300
400
Output Frequency (MHz)
500
600
30
0
G047
Figure 47. Channel Isolation vs Output Frequency
100
200
300
400
Output Frequency (dB)
500
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Figure 48. SFDR vs Output Frequency
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Typical Characteristics (continued)
All plots are at 25°C, nominal supply voltage, fDAC = 1250 MSPS, 4x interpolation, NCO enabled, Mixer Gain disabled, QMC
enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20-mA full-scale output current with 4:1 transformer
(unless otherwise noted)
100
BGA
MrQFN
90
IMD3 (dBc)
80
70
60
50
40
30
0
100
200
300
400
Output Frequency (dB)
500
600
G049
Figure 49. IMD3 vs Output Frequency
26
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7 Detailed Description
7.1 Overview
The DAC3484 includes a quad-channel, 16-bit digital-to-analog converter (DAC) with up to 1.25 GSPS sample
rate, a 16-bit LVDS data bus with on-chip termination, FIFO, data pattern checker, and parity test. The device
includes 2x to 16x digital interpolation filters with over 90dB of stop-band attenuation, reconstruction filters,
independent complex mixers, a low jitter clock multiplier, and digital Quadrature Modulator Correction (QMC).
Full synchronization of multiple devices is possible with the DAC3484. It is an ideal device for next generation
communication systems.
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FRAMEN
De-interleave
8 Sample FIFO
100
16
11 taps
x2
x2
x2
x2
LVDS
AVDD
DACVDD
AB-QMC
Gain and Phase
11 taps
BIASJ
16-b
DACA
IOUTAP
IOUTAN
A-Group
Delay
9 taps
B-Group
Delay
x
sin(x)
16-b
DACB
IOUTBP
IOUTBN
QMC
B-offset
CMIX Control
(±n*Fs/8)
2x–16x Interpolation
FIR0
FIR1
FIR2
DAC
Gain
FIR3
16
x2
x2
x2
QMC
C-offset
FIR4
x2
CD-Channel
59 taps
23 taps
11 taps
11 taps
x2
x2
x2
x2
16
Frame Strobe and
Optional Parity
cos
x
sin(x)
16-b
DACC
IOUTCP
IOUTCN
C-Group
Delay
9 taps
D-Group
Delay
x
sin(x)
16-b
DACD
IOUTDP
IOUTDN
QMC
D-offset
sin
CD
32-Bit NCO
OSTRP
Temp
Sensor
Control Interface
LVPECL
TESTMODE
ALARM
SLEEP
RESETB
TXENABLE
SCLK
SDIO
SDENB
SDO
OSTRN
AVDD
IOVDD
FRAMEP
•
•
•
23 taps
x
sin(x)
GND
SYNCN
x2
59 taps
LVDS
100
SYNCP
LVDS
100
D0N
FIR4
CD-QMC
Gain and Phase
100
•
•
•
•
•
•
D0P
x2
EXTIO
QMC
A-offset
sin
FIR3
AB-Channel
LVDS
Programmable Delay
D15N
x2
16
Pattern Test
D15P
FIR2
FIR1
LVDS
100
PARITYN
VFUSE
cos
FIR0
x2
PARITYP
1.2-V
Reference
AB
32-Bit NCO
Programmable
Delay
Complex Mixer
(FMIX or CMIX)
DATACLKN
Clock Distribution
LVDS
100
DATACLKP
DIGVDD
Low Jitter
PLL
LVPECL
DACCLKN
Complex Mixer
(FMIX or CMIX)
DACCLKP
LPF
CLKVDD
PLLAVDD
7.2 Functional Block Diagram
B0464-01
28
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7.3 Feature Description
7.3.1 Serial Interface
The serial port of the DAC3484 is a flexible serial interface which communicates with industry standard
microprocessors and microcontrollers. The interface provides read/write access to all registers used to define the
operating modes of DAC3484. It is compatible with most synchronous transfer formats and can be configured as
a 3 or 4 pin interface by sif4_ena in register config2. In both configurations, SCLK is the serial interface input
clock and SDENB is serial interface enable. For 3 pin configuration, SDIO is a bidirectional pin for both data in
and data out. For 4 pin configuration, SDIO is data in only and SDO is data out only. Data is input into the device
with the rising edge of SCLK. Data is output from the device on the falling edge of SCLK.
Each read/write operation is framed by signal SDENB (Serial Data Enable Bar) asserted low. The first frame byte
is the instruction cycle which identifies the following data transfer cycle as read or write as well as the 7-bit
address to be accessed. Table 1 indicates the function of each bit in the instruction cycle and is followed by a
detailed description of each bit. The data transfer cycle consists of two bytes.
Table 1. Instruction Byte of the Serial Interface
BIT
7 (MSB)
6
5
4
3
2
1
0 (LSB)
Description
R/W
A6
A5
A4
A3
A2
A1
A0
R/W
Identifies the following data transfer cycle as a read or write operation. A high indicates a read
operation from DAC3484 and a low indicates a write operation to DAC3484.
[A6 : A0]
Identifies the address of the register to be accessed during the read or write operation.
Figure 50 shows the serial interface timing diagram for a DAC3484 write operation. SCLK is the serial interface
clock input to DAC3484. Serial data enable SDENB is an active low input to DAC3484. SDIO is serial data in.
Input data to DAC3484 is clocked on the rising edges of SCLK.
Instruction Cycle
Data Transfer Cycle
SDENB
SCLK
SDIO
rwb
A6
A5
A4
tS(SDENB)
A3
A2
A1
A0
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
t(SCLK)
SDENB
SCLK
SDIO
tH(SDIO)
tS(SDIO)
T0521-01
Figure 50. Serial Interface Write Timing Diagram
Figure 51 shows the serial interface timing diagram for a DAC3484 read operation. SCLK is the serial interface
clock input to DAC3484. Serial data enable SDENB is an active low input to DAC3484. SDIO is serial data in
during the instruction cycle. In 3 pin configuration, SDIO is data out from the DAC3484 during the data transfer
cycle, while SDO is in a high-impedance state. In 4 pin configuration, SDO is data out from the DAC3484 during
the data transfer cycle. At the end of the data transfer, SDIO and SDO will output low on the final falling edge of
SCLK until the rising edge of SDENB when they will 3-state.
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Instruction Cycle
Data Transfer Cycle
SDENB
SCLK
SDIO
rwb
A6
A5
A4
A3
A2
A1
SDO
A0
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
SDENB
SCLK
SDIO
SDO
Data n
Data n – 1
td(Data)
T0522-01
Figure 51. Serial Interface Read Timing Diagram
7.3.2 Data Interface
The DAC3484 has a 16-bit LVDS bus that accepts quad, 16-bit data either in word-wide or dual byte-wide
formats. The quad, 16-bit data can be input to the device using either a single-bus, 16-bit interface or a dual-bus,
8-bit interface. The selection between the two modes is done through 16bit_in in the config2 register. The LVDS
bus inputs in each mode are shown in Table 2.
Table 2. LVDS Bus Input Assignment
INPUT MODE
PINS
Word-wide
D[15..0] → Data for paths A, B, C
and D
Byte-wide
D[15..8] → Data for paths A and B
D[7..0] → Data for paths C and D
Data is sampled by the LVDS double data rate (DDR) clock DATACLK. Setup and hold requirements must be
met for proper sampling.
For both input bus modes, a sync signal, either FRAME or SYNC, can sync the FIFO read and/or write pointers.
In byte-wide mode the sync source is needed to establish the correct sample boundaries.
The sync signal, either FRAME or SYNC, can be either a pulse or a periodic signal where the sync period
corresponds to multiples of 8 samples. FRAME or SYNC is sampled by a rising edge in DATACLK. The pulsewidth t(FRAME_SYNC) needs to be at least equal to 1/2 of the DATACLK period.
For both input bus mode, the value in FRAME sampled by the next falling edge in DATACLK can be used as a
block parity value. This feature is enabled by setting frame_parity_ena in register config1 to 1b. Refer to Parity
Check Test section for more detail
7.3.2.1 Word-Wide Format
The single-bus, 16-bit interface is selected by setting 16bit_in to 1b in the config2 register. In this mode the 16-bit
data for channels A, B, C and D is input word-wide interleaved in the form A0, B0, C0, D0, A1… into the
D[15:0]P/N LVDS bus. Data into the DAC3484 is formatted according to the diagram shown in Figure 52 where
index 0 is the data LSB and index 15 is the data MSB.
30
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SAMPLE 0
D[15:0]P/N
A0
[15:0]
B0
[15:0]
C0
[15:0]
SAMPLE 1
D0
[15:0]
A1
[15:0]
B1
[15:0]
C1
[15:0]
D1
[15:0]
DATACLKP/N (DDR)
t(FRAME_SYNC)
Sync
Option #1
Optional
Parity Bit
FRAMEP/N
t(FRAME_SYNC)
Sync
Option #2
SYNCP/N
T0533-01
Figure 52. Word-wide Data Transmission Format
7.3.2.2 Byte-Wide Format
The dual-bus, 8-bit interface is selected by setting 16bit_in to 0b in the config2 register. In this mode the 16-bit
data for channels A and B is interleaved in the form A0[15:8], A0[7:0], B0[15:8], B0[7:0], A1[15:8]… into the
D[15:8]P/N LVDS inputs. Similarly data for channels C and D is interleaved into the D[7:0]P/N LVDS inputs. Data
into the DAC3484 is formatted according to the diagram shown in Figure 53 where index 0 is the data LSB and
index 15 is the data MSB.
SAMPLE 0
SAMPLE 1
D[15:8]P/N
A0
[15:8]
A0
[7:0]
B0
[15:8]
B0
[7:0]
A1
[15:8]
A1
[7:0]
B1
[15:8]
B1
[7:0]
D[7:0]P/N
C0
[15:8]
C0
[7:0]
D0
[15:8]
D0
[7:0]
C1
[15:8]
C1
[7:0]
D1
[15:8]
D1
[7:0]
DATACLKP/N (DDR)
t(FRAME_SYNC)
Sync
Option #1
FRAMEP/N
Optional
Parity Bit
t(FRAME_SYNC)
Sync
Option #2
SYNCP/N
T0534-01
Figure 53. Byte-wide Data Transmission Format
7.3.3 Input FIFO
The DAC3484 includes a 4-channel, 16-bits wide, and 8-samples deep input FIFO which acts as an elastic
buffer. The purpose of the FIFO is to absorb any timing variations between the input data and the internal DAC
data rate clock such as the ones resulting from clock-to-data variations from the data source.
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Figure 54 shows a simplified block diagram of the FIFO. The following sections provide brief overviews of the
FIFO, device synchronization, and device clocking. For more details of the topics, please refer to application note
SLAA584.
Clock Handoff
Initial
Position
D[15:0]
B-Data, 16-Bit
Frame Align
C-Data, 16-Bit
D-Data, 16-Bit
0 ... 7
Write Pointer
A-Data, 16-Bit
16-Bit
Output Side
Clocked by FIFO Out Clock
(DACCLK/Interpolation Factor)
FIFO:
4 x 16-Bits Wide
8-Samples deep
0
Sample 0
A0[15:0], B0[15:0], C0[15:0], D0[15:0]
0
1
Sample 0
A1[15:0], B1[15:0], C1[15:0], D1[15:0]
1
2
Sample 0
A2[15:0], B2[15:0], C2[15:0], D2[15:0]
2
3
Sample 0
A3[15:0], B3[15:0], C3[15:0], D3[15:0]
3
4
Sample 0
A4[15:0], B4[15:0], C4[15:0], D4[15:0]
4
5
Sample 0
A5[15:0], B5[15:0], C5[15:0], D5[15:0]
5
6
Sample 0
A6[15:0], B6[15:0], C6[15:0], D6[15:0]
6
7
Sample 0
A7[15:0], B7[15:0], C7[15:0], D7[15:0]
7
64-Bit
16-Bit
FRAME/
SYNC
Write Pointer Reset
FIFO Reset
16-Bit
64-Bit
Initial
Position
0 ... 7
Read Pointer
Input Side
Clocked by DATACLK
x2
Two Cycles to Capture 64 Bits
(16 for Each Channel)
16-Bit
16-Bit
16-Bit
FIFO A Output
FIFO B Output
FIFO C Output
FIFO D Output
Read Pointer Reset
fifo_offset(2:0)
S
M
syncsel_fifoout
OSTR
syncsel_fifoin
S (Single Sync Source Mode): Reset handoff from
input side to output side
M (Dual Sync Sources Mode): OSTR resets read
pointer. Allows Multi-DAC synchronization
B0465-01
Figure 54. DAC3484 FIFO Block Diagram
Data is written to the device 16-bits at a time on the rising and falling edges of DATACLK. In order to form a
complete 64-bit wide sample (16-bit A-data, 16-bit B-data, 16-bit C-data, and 16-bit D-data) two DATACLK
periods are required. Each 64-bit wide sample is written into the FIFO at the address indicated by the write
pointer. Similarly, data from the FIFO is read by the FIFO Out Clock 64-bits at a time from the address indicated
by the read pointer. The FIFO Out Clock is generated internally from the DACCLK signal and its rate is equal to
DACCLK/Interpolation. Each time a FIFO write or FIFO read is done the corresponding pointer moves to the next
address.
The reset position for the FIFO read and write pointers is set by default to addresses 0 and 4 as shown in
Figure 54. This offset gives optimal margin within the FIFO. The default read pointer location can be set to
another value using fifo_offset(2:0) in register config9 (address 4 by default). Under normal conditions data is
written-to and read-from the FIFO at the same rate and consequently the write and read pointer gap remains
constant. If the FIFO write and read rates are different, the corresponding pointers will be cycling at different
speeds which could result in pointer collision. Under this condition the FIFO attempts to read and write data from
the same address at the same time which will result in errors and thus must be avoided.
The write pointer sync source is selected by syncsel_fifoin(3:0) in register config32. In most applications either
FRAME or SYNC are used to reset the write pointer. Unlike DATA, the sync signal is latched only on the rising
edges of DATACLK. A rising edge on the sync signal source causes the pointer to return to its original position.
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Similarly, the read pointer sync source is selected by syncsel_fifoout(3:0). The write pointer sync source can be
set to reset the read pointer as well. In this case, FIFO Out clock will recapture the write pointer sync signal to
reset the read pointer. This clock domain transfer (DATACLK to FIFO Out Clock) results in phase ambiguity of
the reset signal, and will create latency variation based on the capture edge of the FIFO Out Clock. Since the
reset signal also synchronizes the clock divider circuit for the FIFO Out Clock generation, the latency variation
also includes the capture edge of the DACCLK cycle in the clock divider stage. Ultimately, the variation in
capture edge of both the FIFO Out Clock and the DACCLK limits the precise control of the output timing latency.
The full latency control of the DAC will be difficult and is not recommended in this setup.
NOTE
For full latency control of the DAC, refer to the Dual Sync Source mode section of the data
sheet.
To alleviate this, the device offers the alternative of resetting the FIFO read pointer independently of the write
pointer by using the OSTR signal. The OSTR signal is sampled by DACCLK and must satisfy the timing
requirements in the specifications table. In order to minimize the skew it is recommended to use the same clock
distribution device such as Texas Instruments CDCE62005 or LMK0480x family to provide the DACCLK and
OSTR signals to all the DAC3484 devices in the system. Swapping the polarity of the DACCLK outputs with
respect to the OSTR ones establishes proper phase relationship.
The FIFO pointers reset procedure can be done periodically or only once during initialization as the pointers
automatically return to the initial position when the FIFO has been filled. To reset the FIFO periodically, it is
necessary to have the FRAME, SYNC, and OSTR signals to repeat at multiples of 8 FIFO samples. To disable
FIFO reset, set syncsel_fifoin(3:0) and syncsel_fifoout(3:0) to 0000b.
The frequency limitation for FRAME and SYNC signals are the following:
fsync = fDATACLK/(n x 16) where n = 1, 2, … for Word-Wide and Byte-Wide Mode
The frequency limitation for the OSTR signal is the following:
fOSTR = fDAC/(n x interpolation x 8) where n = 1, 2, …
The frequencies above are at maximum when n = 1. This is when the FRAME, SYNC, or OSTR have a rising
edge transition every 8 FIFO samples. The occurrence can be made less frequent by setting n > 1, for example,
every n × 8 FIFO samples.
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LVDS Pairs (Data Source)
D[15:0]P/N
tS(DATA)
tH(DATA)
DATACLKP/N
(DDR)
tH(DATA)
tS(DATA)
FRAMEP/N
SYNCP/N
LVPECL Pairs (Clock Source)
tS(DATA)
tH(DATA)
Resets Write Pointer to Position 0
DACCLKP/N
2x Interpolation
tS(OSTR)
tH(OSTR)
OSTRP/N
(optionally internal
sync from Write Reset)
Resets Read Pointer to Position
Set by fifo_offset (4 by Default)
T0535-01
Figure 55. FIFO Write and Read Descriptions
7.3.4 FIFO Modes of Operation
The DAC3484 input FIFO can be completely bypassed through registers config0 and config32. The register
configuration for each mode is described in Table 3.
Register
Control Bits
config0
fifo_ena
config32
syncsel_fifoout(3:0)
Table 3. FIFO Operation Modes
config0 and config32 FIFO Bits
FIFO MODE
fifo_ena
syncsel_fifoout
BIT 3: sif_sync
BIT 2: OSTR
BIT 1: FRAME
BIT 0: SYNC
Dual Sync Sources
1
0
1
0
0
Single Sync
Source
1
0
0
1 or 0 Depends on the sync
source
1 or 0 Depends on the
sync source
Bypass
0
X
X
X
X
7.3.4.1 Dual Sync Sources Mode
This is the recommended mode of operation for those applications that require precise control of the output
timing. In Dual Sync Sources mode, the FIFO write and read pointers are reset independently. The FIFO write
pointer is reset using the LVDS FRAME or SYNC signal, and the FIFO read pointer is reset using the LVPECL
OSTR signal. This allows LVPECL OSTR signal to control the phase of the output for either a single chip or
multiple chips. Multiple devices can be fully synchronized in this mode.
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7.3.4.2 Single Sync Source Mode
In Single Sync Source mode, the FIFO write and read pointers are reset from the same source, either LVDS
FRAME or LVDS SYNC signal. As described in the Input FIFO section, this mode has latency variations in both
the FIFO Out Clock and DAC Clock between the multiple DAC devices. Applications requiring exact output timing
control will need Dual Sync Sources mode instead of Single Sync Source Mode. A rising edge for FIFO and
clock divider sync is recommended. Periodic sync signal is not recommended due to non-deterministic latency of
the sync signal through the clock domain transfer.
7.3.4.3 Bypass Mode
In FIFO bypass mode, the FIFO block is not used. As a result the input data is handed off from the DATACLK to
the DACCLK domain without any compensation. In this mode the relationship between DATACLK and DACCLK
is critical and used as a synchronizing mechanism for the internal logic. Due to the this constraint this mode is
not recommended. The effects of bypassing the FIFO are the following:
• The FIFO pointers have no effect on the data path or handoff.
• The FIFO will not be able to pass the controls signals from the LVDS FRAME and LVDS SYNC to digital
circuits after the FIFO. These digital circuits mainly are quadrature modulation corrections circuits, complex
mixer circuits, and numerical controlled oscillator circuits.
7.3.5 Clocking Modes
The DAC3484 has a dual clock setup in which a DAC clock signal is used to clock the DAC cores and internal
digital logic and a separate DATA clock is used to clock the input LVDS receivers and FIFO input. The DAC3484
DAC clock signal can be sourced directly or generated through an on-chip low-jitter phase-locked loop (PLL).
In those applications requiring extremely low noise it is recommended to bypass the PLL and source the DAC
clock directly from a high-quality external clock to the DACCLK input. In most applications system clocking can
be simplified by using the on-chip PLL to generate the DAC core clock while still satisfying performance
requirements. In this case the DACCLK pins are used as the reference frequency input to the PLL.
16-Bit
DACI
DACCLK
PLL
Clock Distribution
to Digital
VCO/
Dividers
16-Bit
DACQ
pll_ena
B0452-01
Figure 56. Top Level Clock Diagram
7.3.5.1 PLL Bypass Mode
In PLL bypass mode a very high quality clock is sourced to the DACCLK inputs. This clock is used to directly
clock the DAC3484 DAC sample rate clock. This mode gives the device best performance and is recommended
for extremely demanding applications.
The bypass mode is selected by setting the following:
1. pll_ena bit in register config24 to 0b to bypass the PLL circuitry.
2. pll_sleep bit in register config26 to 1b to put the PLL and VCO into sleep mode.
7.3.5.2 PLL Mode
In this mode the clock at the DACCLK input functions as a reference clock source to the on-chip PLL. The onchip PLL will then multiply this reference clock to supply a higher frequency DAC sample rate clock. Figure 57
shows the block diagram of the PLL circuit.
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OSTR (Internally Generated)
External Loop
Filter
DACCLKP
REFCLK
DACCLKN
PFD
and
CP
N
Divider
SYNCP
Prescaler
SYNC_PLL
Internal Loop
Filter
SYNCN
Note:
The PLL generates internal OSTR signal. In this mode
external LVPECL OSTR signal is not required.
DACCLK
VCO
M
Divider
If the DAC is configured with PLL enabled with Dual Sync
Sources mode, then the PFD frequency has to be the predefined OSTR frequency.
B0453-01
Figure 57. PLL Block Diagram
The DAC3484 PLL mode is selected by setting the following:
1. pll_ena bit in register config24 to 1b to route to the PLL clock path.
2. pll_sleep bit in register config26 to 0b to enable the PLL and VCO.
The output frequency of the VCO is designed to be the in the range from 3.3GHz to 4.0GHz. The prescaler
value, pll_p(2:0) in register config24, should be chosen such that the product of the prescaler value and DAC
sample rate clock is within the VCO range. To maintain optimal PLL loop, the coarse tune bits, pll_vco(5:0) in
register config26, can adjust the center frequency of the VCO towards the product of the prescaler value and
DAC sample rate clock. Figure 58 shows a typical relationship between coarse tune bits and VCO center
frequency.
4000
Coarse-Tuning Bits @
VCO Frequency (MHz)
3900
VCO Frequency (MHz ) - 3253
11.6
3800
3700
3600
3500
3400
3300
0
8
16
24
32
40
48
56
64
Coarse-Tuning Bits
Figure 58. Typical PLL/VCO Lock Range vs Coarse Tuning Bits
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Common wireless infrastructure frequencies (614.4 MHz, 737.28 MHz, 1.2288 GHz, ...) are generated from this
VCO frequency in conjunction with the pre-scaler setting as shown in Table 4.
Table 4. VCO Operation
VCO FREQUENCY
(MHz)
PRE-SCALE DIVIDER
DESIRED DACCLK (MHz)
pll_p(2:0)
3440.64
7
491.52
111
3686.4
6
614.4
110
3686.4
5
737.28
101
3686.4
3
1228.8
011
The M divider is used to determine the phase-frequency-detector (PFD) and charge-pump (CP) frequency.
Table 5. PFD and CP Operation
DACCLK FREQUENCY
(MHz)
M DIVIDER
PDF UPDATE RATE (MHz)
pll_m(7:0)
491.52
4
122.88
00000100
491.52
8
61.44
00001000
491.52
16
30.72
00010000
491.52
32
15.36
00100000
The N divider in the loop allows the PFD to operate at a lower frequency than the reference clock. Both M and N
dividers can keep the PFD frequency below 155 MHz for peak operation.
The overall divide ratio inside the loop is the product of the Pre-Scale and M dividers (P * M) and the following
guidelines should be followed:
• The overall divide ratio range is from 24 to 480
• When the overall divide ratio is less than 120, the internal loop filter can guarantee a stable loop
• When the overall divide ratio is greater than 120, an external loop filter or double charge pump is required to
ensure loop stability
The single- and double-charge-pump current option are selected by setting pll_cp in register config24 to 01b and
11b, respectively. When using the double-charge-pump setting, an external loop filter is not required. If an
external filter is required, the following filter should be connected to the LPF pin (A1 for RKD package and D12
for ZAY package):
LPF
R = 1 kΩ
C2 = 1 nF
C1 = 100 nF
S0514-01
Figure 59. Recommended External Loop Filter
The PLL generates an internal OSTR signal and does not require the external LVPECL OSTR signal. The OSTR
signal is buffered from the N-divider output in the PLL block, and the frequency of the signal is the same as the
PFD frequency. Therefore, using PLL with Dual Sync Sources mode would require the PFD frequency to be the
pre-defined OSTR frequency. This will allow the FIFO to be synced correctly by the internal OSTR.
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7.3.6 FIR Filters
Figure 60 through Figure 63 show the magnitude spectrum response for the FIR0, FIR1, FIR2 and FIR3
interpolating filters where fIN is the input data rate to the FIR filter. Figure 64 to Figure 67 show the composite
filter response for 2x, 4x, 8x and 16x interpolation. The transition band for all interpolation settings is from 0.4 to
0.6 x fDATA (the input data rate to the device) with <0.001dB of pass-band ripple and >90dB stop-band
attenuation.
The DAC3484 also has a 9-tap inverse sinc filter (FIR4) that runs at the DAC update rate (fDAC) that can be used
to flatten the frequency response of the sample-and-hold output. The DAC sample-and-hold output sets the
output current and holds it constant for one DAC clock cycle until the next sample, resulting in the well-known
sin(x)/x or sinc(x) frequency response (Figure 68, red line). The inverse sinc filter response (Figure 68, blue line)
has the opposite frequency response from 0 to 0.4 x Fdac, resulting in the combined response (Figure 68, green
line). Between 0 to 0.4 x fDAC, the inverse sinc filter compensates the sample-and-hold roll-off with less than
0.03dB error.
The inverse sinc filter has a gain >1 at all frequencies. Therefore, the signal input to FIR4 must be reduced from
full scale to prevent saturation in the filter. The amount of back-off required depends on the signal frequency, and
is set such that at the signal frequencies the combination of the input signal and filter response is less than 1
(0dB). For example, if the signal input to FIR4 is at 0.25 x fDAC, the response of FIR4 is 0.9dB, and the signal
must be backed off from full scale by 0.9dB to avoid saturation. The gain function in the QMC blocks can be
used to reduce the amplitude of the input signal. The advantage of FIR4 having a positive gain at all frequencies
is that the user is then able to optimize the back-off of the signal based on its frequency.
The filter taps for all digital filters are listed in Table 6. Note that the loss of signal amplitude may result in lower
SNR due to decrease in signal amplitude.
20
20
0
0
–20
–20
–40
–40
Magnitude (dB)
Magnitude (dB)
SPACER
–60
–80
–100
–60
–80
–100
–120
–120
–140
–140
–160
–160
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
f/fIN
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
f/fIN
G048
Figure 60. Magnitude Spectrum for FIR0
SPACER
38
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G049
Figure 61. Magnitude Spectrum for FIR1
SPACER
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20
20
0
0
–20
–20
–40
–40
Magnitude (dB)
Magnitude (dB)
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–60
–80
–100
–60
–80
–100
–120
–120
–140
–140
–160
–160
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
0.1
0.2
0.3
0.4
f/fIN
0.5
0.6
0.7
0.8
0.9
f/fIN
G050
G051
Figure 63. Magnitude Spectrum for FIR3
SPACER
20
20
0
0
–20
–20
–40
–40
Magnitude (dB)
Magnitude (dB)
Figure 62. Magnitude Spectrum for FIR2
SPACER
–60
–80
–100
–60
–80
–100
–120
–120
–140
–140
–160
–160
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0
1
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
f/fDATA
f/fDATA
G053
G052
Figure 64. 2x Interpolation Composite Response
SPACER
Figure 65. 4x Interpolation Composite Response
SPACER
20
20
0
0
–20
–20
–40
–40
Magnitude (dB)
Magnitude (dB)
1
–60
–80
–100
–60
–80
–100
–120
–120
–140
–140
–160
–160
0
0.5
1
1.5
2
2.5
3
3.5
4
0
f/fDATA
1
2
3
4
5
6
7
8
f/fDATA
G054
Figure 66. 8x Interpolation Composite Response
SPACER
G055
Figure 67. 16x Interpolation Composite Response
SPACER
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4
3
FIR4
Magnitude (dB)
2
1
Corrected
0
–1
–2
sin(x)/x
–3
–4
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
f/fDAC
G056
Figure 68. Magnitude Spectrum for Inverse Sinc Filter
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Table 6. FIR Filter Coefficients
NON-INTERPOLATING
INVERSE-SINC FILTER
INTERPOLATING HALF-BAND FILTERS
FIR0
FIR1
59 TAPS
FIR2
23 TAPS
FIR3
11 TAPS
FIR4
11 TAPS
9 TAPS
6
6
-12
-12
29
29
3
3
1
1
0
0
0
0
0
0
0
0
-4
-4
-19
-19
84
84
-214
-214
-25
-25
13
13
0
0
0
0
0
0
0
0
-50
-50
47
47
-336
-336
1209
1209
150
150
592 (1)
0
0
0
0
2048 (1)
-100
-100
1006
1006
0
0
0
0
192
192
-2691
-2691
0
0
0
0
-342
-342
10141
10141
0
0
16384 (1)
572
572
0
0
-914
-914
0
0
1409
1409
0
0
-2119
-2119
0
0
3152
3152
0
0
-4729
-4729
0
0
7420
7420
0
0
-13334
-13334
0
0
41527
41527
256 (1)
65536 (1)
(1)
Center taps are highlighted in BOLD
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7.3.7 Complex Signal Mixer
The DAC3484 has two paths of complex signal mixer blocks that contain two full complex mixer (FMIX) blocks
and power saving coarse mixer (CMIX) blocks. The signal path is shown in Figure 69.
I Data In
(A)
Q Data In
(B)
16
16
Fs/2
Mixer
16
16
±Fs/4
Mixer
16
CMIX<1>
16
Complex
Signal
Multiplier
16
sine
16
CMIX<2> CMIX<0>
I Data Out
(A)
16
Q Data Out
(B)
cosine
16
CMIX<3>
sine
16
cosine sine
16
16
(AB)
Numerically
Controlled
Oscillator
NCO_ENA
cosine
16
Fixed Fs/8
Oscillator
B0471-02
Figure 69. Path of Complex Signal Mixer
7.3.7.1 Full Complex Mixer
The two FMIX blocks operate with independent Numerically Controlled Oscillators (NCOs) and enable flexible
frequency placement without imposing additional limitations in the signal bandwidth. The NCOs have 32-bit
frequency registers (phaseaddAB(31:0) and phaseaddCD(31:0)) and 16-bit phase registers (phaseoffsetAB(15:0)
and phaseoffsetCD(15:0)) that generate the sine and cosine terms for the complex mixing. The NCO block
diagram is shown in Figure 70.
32
16
Frequency
Register
32
Σ
32
Accumulator
CLK
32
16
16
Σ
sin
Look-Up
Table
16
cos
RESET
16
fDAC
NCO SYNC
via
syncsel_NCO[3:0]
Phase
Register
B0026-03
Figure 70. NCO Block Diagram
Synchronization of the NCOs occurs by resetting the NCO accumulators to zero. The synchronization source is
selected by syncsel_NCO(3:0) in config31. The frequency word in the phaseaddAB(31:0) and phaseaddCD(31:0)
registers is added to the accumulators every clock cycle, fDAC. The output frequency of the NCO is:
freq ´ fNCO _ CLK
fNCO =
232
(1)
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With the complex mixer enabled, the two channels in the mixer path are treated as complex vectors of the form
IIN(t) + j QIN(t). The complex signal multiplier (shown in Figure 71) will multiply the complex channels with the sine
and cosine terms generated by the NCO. The resulting output, IOUT(t) + j QOUT(t), of the complex signal multiplier
is:
IOUT(t) = (IIN(t)cos(2πfNCOt + δ) – QIN(t)sin(2πfNCOt + δ)) × 2(mixer_gain – 1)
QOUT(t) = (IIN(t)sin(2πfNCOt + δ) + QIN(t)cos(2πfNCOt + δ)) × 2(mixer_gain – 1)
where t is the time since the last resetting of the NCO accumulator, δ is the phase offset value and mixer_gain is
either 0 or 1. δ is given by:
δ = 2π × phase_offsetAB/CD(15:0)/216
The mixer_gain option allows the output signals of the multiplier to reduce by half (6dB). See Mixer Gain section
for details.
IIN(t)
16
QIN(t)
16
IOUT(t)
16
QOUT(t)
16
16
16
cosine
sine
Figure 71. Complex Signal Multiplier
7.3.7.2 Coarse Complex Mixer
In addition to the full complex mixer, the DAC3484 also has a coarse mixer block capable of shifting the input
signal spectrum by the fixed mixing frequencies ±n×fS/8. Using the coarse mixer instead of the full mixer lowers
power consumption.
The output of the fs/2, fs/4, and –fs/4 mixer block is:
IOUT(t) = I(t)cos(2πfCMIXt) – Q(t)sin(2πfCMIXt)
QOUT(t) = I(t)sin(2πfCMIXt) + Q(t)cos(2πfCMIXt)
Since the sine and the cosine terms are a function of fs/2, fs/4, or –fs/4 mixing frequencies, the possible resulting
value of the terms will only be 1, -1, or 0. The simplified mathematics allows the complex signal multiplier to be
bypassed in any one of the modes, thus mixer gain is not available. The fs/2, fs/4, and –fs/4 mixer blocks
performs mixing through negating and swapping of I/Q channel on certain sequence of samples. Table 7 shows
the algorithm used for those mixer blocks.
Table 7. Fs/2, Fs/4, and –Fs/4 Mixing Sequence
MODE
Normal (mixer bypassed)
fs/2
MIXING SEQUENCE
Iout = {+I1, +I2, +I3, +I4…}
Qout = {+Q1, +Q2, +Q3, +Q4…}
Iout = {+I1, -I2, +I3, -I4…}
Qout = {+Q1, -Q2, +Q3, -Q4…}
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Table 7. Fs/2, Fs/4, and –Fs/4 Mixing Sequence (continued)
MODE
MIXING SEQUENCE
Iout = {+I1, -Q2, -I3, +Q4…}
fs/4
Qout = {+Q1, +I2, -Q3, -I4…}
Iout = {+I1, +Q2, -I3, -Q4…}
-fs/4
Qout = {+Q1, -I2, -Q3, +I4…}
The fs/8 mixer can be enabled along with various combinations of fs/2, fs/4, and –fs/4 mixer. Since the fs/8 mixer
uses the complex signal multiplier block with fixed fs/8 sine and cosine term, the output of the multiplier is:
IOUT(t) = (IIN(t)cos(2πfNCOt + δ) – QIN(t)sin(2πfNCOt + δ)) × 2(mixer_gain – 1)
QOUT(t) = (IIN(t)sin(2πfNCOt + δ) + QIN(t)cos(2πfNCOt + δ)) × 2(mixer_gain – 1)
where fCMIX is the fixed mixing frequency selected by cmix(3:0). The mixing combinations are described in
Table 8. The mixer_gain option allows the output signals of the multiplier to reduce by half (6dB). See Mixer Gain
section for details.
Table 8. Coarse Mixer Combinations
cmix(3:0)
Fs/8 MIXER
cmix(3)
Fs/4 MIXER
cmix(2)
Fs/2 MIXER
cmix(1)
–Fs/4 MIXER
cmix(0)
MIXING MODE
0000
Disabled
Disabled
Disabled
Disabled
No mixing
0001
Disabled
Disabled
Disabled
Enabled
–Fs/4
0010
Disabled
Disabled
Enabled
Disabled
Fs/2
0100
Disabled
Enabled
Disabled
Disabled
+Fs/4
1000
Enabled
Disabled
Disabled
Disabled
+Fs/8
1010
Enabled
Disabled
Enabled
Disabled
–3Fs/8
1100
Enabled
Enabled
Disabled
Disabled
+3Fs/8
1110
Enabled
Enabled
Enabled
Disabled
–Fs/8
All others
–
–
–
–
Not recommended
7.3.7.3 Mixer Gain
The maximum output amplitude out of the complex signal multiplier (i.e., FMIX mode or CMIX mode with fs/8
mixer enabled) occurs if IIN(t) and QIN(t) are simultaneously full scale amplitude and the sine and cosine
arguments are equal to 2π x fMIXt + δ (2N-1) x π/4, where N = 1, 2, 3, etc....
cosine
sine
Max output occurs when both
sine and cosine are 0.707
M0221-01
Figure 72. Maximum Output of the Complex Signal Multiplier
With mixer_gain = 1 and both IIN(t) and QIN(t) are simultaneously full scale amplitude, the maximum output
possible out of the complex signal multiplier is 0.707 + 0.707 = 1.414 (or 3dB). This configuration can cause
clipping of the signal and should therefore be used with caution.
With mixer_gain = 0 in config2, the maximum output possible out of the complex signal multiplier is 0.5 x (0.707
+ 0.707) = 0.707 (or -3dB). This loss in signal power is in most cases undesirable, and it is recommended that
the gain function of the QMC block be used to increase the signal by 3dB to compensate.
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7.3.7.4 Real Channel Upconversion
The mixer in the DAC34H84 treats the A, B, C, and D inputs are complex input data and produces a complex
output for most mixing frequencies. The real input data for each channel can be isolated only when the mixing
frequency is set to normal mode or fs/2 mode. Refer to Table 7 for details.
7.3.8 Quadrature Modulation Correction (QMC)
7.3.8.1 Gain and Phase Correction
The DAC3484 includes a Quadrature Modulator Correction (QMC) block. The QMC blocks provide a mean for
changing the gain and phase of the complex signals to compensate for any I and Q imbalances present in an
analog quadrature modulator. The block diagram for the QMC block is shown in Figure 73. The QMC block
contains 3 programmable parameters.
Register qmc_gainA/B(10:0) and qmc_gainC/D(10:0) controls the I and Q path gains and is an 11-bit unsigned
value with a range of 0 to 1.9990 and the default gain is 1.0000. The implied decimal point for the multiplication
is between bit 9 and bit 10.
Register qmc_phaseAB/CD(11:0) control the phase imbalance between I and Q and is a 12-bit values with a
range of –0.5 to approximately 0.49975. The QMC phase term is not a direct phase rotation but a constant that is
multiplied by each "Q" sample then summed into the "I" sample path. This is an approximation of a true phase
rotation in order to keep the implementation simple. The corresponding phase rotation corresponds to
approximately +26.5 to –26.5 degrees in 4096 steps.
LO feed-through can be minimized by adjusting the DAC offset feature described below.
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qmc_gainA[10:0]
11
16
Σ
I Data In
(A)
16
I Data Out
(A)
12
qmc_phaseAB[11:0]
16
16
Q Data In
(B)
Q Data Out
(B)
11
qmc_gainB[10:0]
qmc_gainC[10:0]
11
16
Σ
I Data In
(C)
16
I Data Out
(C)
12
qmc_phaseCD[11:0]
16
16
Q Data In
(D)
Q Data Out
(D)
11
qmc_gainD[10:0]
B0164-03
Figure 73. QMC Block Diagram
7.3.8.2 Offset Correction
Registers qmc_offsetA(12:0), qmc_offsetB(12:0), qmc_offsetC(12:0) and qmc_offsetD(12:0) can be used to
independently adjust the DC offsets of each channel. The offset values are in represented in 2s-complement
format with a range from -4096 to 4095.
The offset value adds a digital offset to the digital data before digital-to-analog conversion. Since the offset is
added directly to the data it may be necessary to back off the signal to prevent saturation. Both data and offset
values are LSB aligned.
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qmc_offsetA
{–4096, –4095, ..., 4095}
13
16
A Data In
16
B Data In
16
Σ
A Data Out
16
Σ
B Data Out
13
qmc_offsetB
{–4096, –4095, ..., 4095}
qmc_offsetC
{–4096, –4095, ..., 4095}
13
16
C Data In
16
D Data In
16
Σ
C Data Out
16
Σ
D Data Out
13
qmc_offsetD
{–4096, –4095, ..., 4095}
B0165-03
Figure 74. Digital Offset Block Diagram
7.3.8.3 Group Delay Correction
A complex transmitter system typically is consisted of DACs, reconstruction filter network, and I/Q modulator.
Besides the gain and phase mismatch contribution, there could also be timing mismatch contribution from each
components. For instance, the timing mismatch could come from the PCB trace length variation between the I
and Q channels and the group delay variation from the reconstruction filter.
This timing mismatch in the complex transmitter system creates phase mismatch that varies linearly with respect
to frequency. To compensate for the I/Q imbalances due to this mismatch, the DAC3484 has group delay
correction block for each DAC channel. Each DAC channel can adjust its delay through grp_delayA(7:0),
grp_delayB(7:0), grp_delayC(7:0), and grp_delayD(7:0) in register config46 and config47. The group delay
correction, along with gain/phase correction, can be useful for correcting imbalances in wide-band transmitter
system. The maximum delay ranges from 30 ps to 100 ps and is dependent on DAC sample clock. Contact TI for
specific application information.
7.3.9 Temperature Sensor
The DAC3484 incorporates a temperature sensor block which monitors the temperature by measuring the
voltage across 2 transistors. The voltage is converted to an 8-bit digital word using a successive-approximation
(SAR) analog to digital conversion process. The result is scaled, limited and formatted as a twos complement
value representing the temperature in degrees Celsius.
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The sampling is controlled by the serial interface signals SDENB and SCLK. If the temperature sensor is enabled
(tsense_sleep = 0b in register config26) a conversion takes place each time the serial port is written or read. The
data is only read and sent out by the digital block when the temperature sensor is read in tempdata(7:0) in
config6. The conversion uses the first eight clocks of the serial clock as the capture and conversion clock, the
data is valid on the falling eighth SCLK. The data is then clocked out of the chip on the rising edge of the ninth
SCLK. No other clocks to the chip are necessary for the temperature sensor operation. As a result the
temperature sensor is enabled even when the device is in sleep mode.
In order for the process described above to operate properly, the serial port read from config6 must be done with
an SCLK period of at least 1 μs. If this is not satisfied the temperature sensor accuracy is greatly reduced.
7.3.10 Data Pattern Checker
The DAC3484 incorporates a simple pattern checker test in order to determine errors in the data interface. The
main cause of failures is setup/hold timing issues. The test mode is enabled by asserting iotest_ena in register
config1. In test mode the analog outputs are deactivated regardless of the state of TXENABLE or sif_texnable in
register config3.
The data pattern key used for the test is 8 words long and is specified by the contents of iotest_pattern[0:7] in
registers config37 through config44. The data pattern key can be modified by changing the contents of these
registers.
The first word in the test frame is determined by a rising edge transition in FRAME or SYNC, depending on the
syncsel_fifoin(4:0) setting in config32. At this transition, the pattern0 word should be input to the data pins.
Patterns 1 through 7 should follow sequentially on each edge of DATACLK (rising and falling). The sequence
should be repeated until the pattern checker test is disabled by setting iotest_ena back to 0b. It is not necessary
to have a rising FRAME or SYNC edge aligned with every pattern0 word, just the first one to mark the beginning
of the series.
Start cycle again with optional rising edge of FRAME or SYNC
D[15:0]P/N
Pattern 0 Pattern 1 Pattern 2 Pattern 3 Pattern 4 Pattern 5 Pattern 6 Pattern 7
[15:0]
[15:0]
[15:0]
[15:0]
[15:0]
[15:0]
[15:0]
[15:0]
DATACLKP/N (DDR)
Sync
Option #1
FRAMEP/N
Sync
Option #2
SYNCP/N
T0528-01
Figure 75. IO Pattern Checker Data Transmission Format
The test mode determines if the 16-bit LVDS data D[15:0]P/N of all the patterns were received correctly by
comparing the received data against the data pattern key. If any of the 16-bit data D[15:0]P/N were received
incorrectly, the corresponding bits in iotest_results(15:0) in register config4 will be set to 1b to indicate bit error
location. Furthermore, the error condition will trigger the alarm_from_iotest bit in register config5 to indicate a
general error in the data interface. When data pattern checker mode is enabled, this alarm in register config5, bit
7 is the only valid alarm. Other alarms in register config5 are not valid and can be disregarded.
For instance, pattern0 is programmed to the default of 0x7A7A. If the received Pattern 0 is 0x7A7B, then bit 0 in
iotest_results(15:0) will be set to 1b to indicate an error in bit 0 location. The alarm_from_iotest will also be set to
1b to report the data transfer error. The user can then narrow down the error from the bit location information and
implement the fix accordingly.
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The alarms can be cleared by writing 0x0000 to iotest_results(15:0) and 0b to alarm_from_iotest through the
serial interface. The serial interface will read back 0s if there are no errors or if the errors are cleared. The
corresponding alarm bit will remain a 1b if the errors remain.
It is recommended to enable the pattern checker and then run the pattern sequence for 100 or more complete
cycles before clearing the iotest_results(15:0) and alarm_from_iotest. This will eliminate the possibility of false
alarms generated during the setup sequence.
Based on the pattern test result, the user can adjust the data source output timing, PCB traces delay, or
DAC3484 CONFIG36 LVDS Programmable delay to help optimize the setup and hold time of the transmitter
system.
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16-Bit
0
Pattern 0
Bit-by-Bit Compare
0
1
Pattern 1
Bit-by-Bit Compare
1
FRAME
or
SYNC
16-Bit
LVDS
Drivers Only one
edge needed
Data
Format
Pattern 0 ... 7
D[15:0]
16-Bit
2
Pattern 2
Bit-by-Bit Compare
3
Pattern 3
Bit-by-Bit Compare
4
Pattern 4
Bit-by-Bit Compare
5
Pattern 5
Bit-by-Bit Compare
DATACLK
2
3
iotest_pattern0
iotest_pattern1
iotest_pattern2
iotest_results[15]
iotest_pattern3
iotest_pattern4
4
iotest_pattern5
5
iotest_pattern6
6
Pattern 6
Bit-by-Bit Compare
6
7
Pattern 7
Bit-by-Bit Compare
7
8-Bit
Input
iotest_pattern7
16-Bit
Input
Bit 15
Results
•
•
•
8-Bit
Input
•
•
•
•
•
•
iotest_results[0]
alarm_from_iotest
All Bits
Results
Bit 0
Results
Go back to 0 after cycle or new
rising edge on FRAME or SYNC
B0457-01
Figure 76. DAC3484 Pattern Check Block Diagram
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7.3.11 Parity Check Test
The DAC3484 has a parity check test that enables continuous validity monitoring of the data received by the
DAC. Parity check testing in combination with the data pattern checker offer an excellent solution for detecting
board assembly issues due to missing pad connections.
For the parity check test, an extra parity bit is added to the data bits to ensure that the total number of set bits
(bits with value 1) is even or odd. This simple scheme is used to detect single or any other odd number of data
transfer errors. Parity testing is implemented in the DAC3484 in two ways: word-by-word parity and block parity.
7.3.11.1 Word-by-Word Parity
Word-by-word parity is the easiest mode to implement. In this mode the additional parity bit is sourced to the
parity input (PARITYP/N) for each data word transfer into the D[15:0]P/N inputs. This mode is enabled by setting
the word_parity_ena bit. The input parity value is defined to be the total number of logic 1s on the 17-bit data
bus, the D[15:0]P/N inputs and the PARITYP/N input. This value, the total number of logic 1s, must match the
parity test selected in the oddeven_parity bit in register config1.
For example, if the oddeven_parity bit is set to 1b for odd parity, then the number of 1s on the 17-bit data bus
should be odd. The DAC will check the data transfer through the parity input. If the data received has odd
number of 1s, then the parity is correct. If the data received has even number of 1s, then the parity is incorrect.
The corresponding alarm for parity error will be set accordingly.
Figure 77 shows the simple XOR structure used to check word parity. Parity is tested independently for data
captured on both rising and falling edges of DATACLK (alarm_rparity and alarm_fparity, respectively). Testing on
both edges helps in determining a possible setup/hold issue. Both alarms are captured individually in register
config5.
alarm_rparity
PARITY
oddeven_parity
D[15:0]
Parity Block
alarm_fparity
DATACLK
B0458-01
Figure 77. DAC3484 Word-by-Word Parity Check
7.3.11.2 Block Parity
The block parity method uses the FRAME signal to determine the boundaries of the data block to compute parity.
This mode is enabled by setting the frame_parity_ena bit in register config1.
A low-to-high transition of FRAME captured with the DATACLK rising edge determines the end point of the parity
block and the beginning of the next one. In this method the parity bit of the completed block corresponds to the
FRAME value captured on the DATACLK falling edge right after the STOP/START point.
The input parity value is defined to be the total number of logic 1s in the data block. A logic HIGH captured on
the falling edge of DATACLK indicates odd parity or odd number of logic 1s, while a logic LOW indicates even
parity or even number of logic 1s. If the expected parity does not match the number of logic 1s in the received
data, then alarm_frame_parity in register config5 will be set to 1b. The main advantage of the block parity mode
is that there is no need for an additional parity LVDS input.
Since the FRAME signal is used for parity testing in addition to FIFO syncing and frame boundary assignment it
is mandatory to take some extra steps to avoid device malfunction. If FRAME is used to reset the FIFO pointers
continuously, the block size must be a multiple of 8 samples (each sample corresponding to 16-bits A, B, C and
D data). In addition since FRAME is used to establish the frame boundary, the parity block must be aligned with
the data frame boundaries.
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A0
[15:0]
D[15:0]P/N
B0
[15:0]
C0
[15:0]
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D0
[15:0]
D[15:0]P/N
DATACLKP/N
(DDR)
•••
•••
High = Odd Parity
Low = Even Parity
FRAMEP/N
Ax
[15:0]
Bx
[15:0]
Cx
[15:0]
Dx
[15:0]
DATACLKP/N
(DDR)
High = Odd Parity
Low = Even Parity
FRAMEP/N
Parity Bit for
Data Block N – 1
Parity Bit for
Data Block N
Data Block N
Stop Point for
Data Block N – 1
Start Point for
Data Block N
Stop Point for
Data Block N
Start Point for
Data Block N + 1
T0527-02
Notes: Rising edge of FRAMEP/N indicates the beginning of data block.
Parity bit for the current data block is latched on falling edge of DATACLK after the start point for next data block.
Figure 78. DAC3484 Block Parity Check (Example shown with Word Wide Mode)
7.3.12 DAC3484 Alarm Monitoring
The DAC3484 includes a flexible set of alarm monitoring that can be used to alert of a possible malfunction
scenario. All the alarm events can be accessed either through the config5 register or through the ALARM pin.
Once an alarm is set, the corresponding alarm bit in register config5 must be reset through the serial interface to
allow further testing. The set of alarms includes the following conditions:
Zero check alarm
• Alarm_from_zerochk. Occurs when the FIFO write pointer has an all zeros pattern. Since the write pointer is a
shift register, all zeros will cause the input pointer to be stuck until the next sync event. When this happens a
sync to the FIFO block is required.
FIFO alarms
• alarm_from_fifo. Occurs when there is a collision in the FIFO pointers or a collision event is close.
– alarm_fifo_2away. Pointers are within two addresses of each other.
– alarm_fifo_1away. Pointers are within one address of each other.
– alarm_fifo_collision. Pointers are equal to each other.
Clock alarms
• clock_gone. Occurs when either the DACCLK or DATACLOCK have been stopped.
– alarm_dacclk_gone. Occurs when the DACCLK has been stopped.
– alarm_dataclk_gone. Occurs when the DATACLK has been stopped.
Pattern checker alarm
• alarm_from_iotest. Occurs when the input data pattern does not match the pattern key.
PLL alarm
• alarm_from_pll. Occurs when the PLL is out of lock.
Parity alarms
• alarm_rparity. Occurs when there is a parity error in the data captured by the rising edge of DATACLKP/N.
The PARITYP/N input is the parity bit (word-by-word parity test).
• alarm_fparity. Occurs when there is a parity error in the data captured by the falling edge of DATACLKP/N.
The PARITYP/N input is the parity bit (word-by-word parity test).
• alarm_frame_parity_err. Occurs when there is a frame parity error when using the FRAME as the parity bit
(block parity test).
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To prevent unexpected DAC outputs from propagating into the transmit channel chain, the clock and alarm_
fifo_collision alarms can be set in config2 to shut-off the DAC output automatically regardless of the state of
TXENABLE or sif_txenable.
Alarm monitoring is implemented as follows:
• Power up the device using the recommended power-up sequence.
• Clear all the alarms in config5 by setting them to 0.
• Unmask those alarms that will generate a hardware interrupt through the ALARM pin in config7.
• Enable automatic DAC shut-off in register config2 if required.
• In the case of an alarm event, the ALARM pin will trigger. If automatic DAC shut-off has been enabled the
DAC outputs will be disabled.
• Read registers config5 to determine which alarm triggered the ALARM pin.
• Correct the error condition and re-synchronize the FIFO.
• Clear the alarms in config5.
• Re-read config5 to ensure the alarm event has been corrected.
• Keep clearing and reading config5 until no error is reported.
For details of alarm monitoring function and behavior, refer to SLAA585.
7.3.13 LVPECL Inputs
Figure 79 shows an equivalent circuit for the DAC input clock (DACCLKP/N) and the output strobe clock
(OSTRP/N).
CLKVDD
250 Ω
2 kΩ
2 kΩ
DACCLKN
OSTRN
DACCLKP
OSTRP
Internal
Digital In
250 Ω
SLEEP
GND
S0515-01
NOTE: Input common mode level is internally biased
Figure 79. DACCLKP/N and OSTRP/N Equivalent Input Circuit
Figure 80 shows the preferred configuration for driving the CLKIN/CLKINC input clock with a differential
ECL/PECL source.
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CAC
0.1 μF
Differential
ECL
or
(LV)PECL
Source
+
CLKIN
CAC
0.1 μF
100 Ω
CLKINC
–
RT
150 Ω
RT
150 Ω
S0029-02
NOTE: Actual RT value depends on differential clock driver output termination recommendation. It is driver type dependent.
Figure 80. Preferred Clock Input Configuration with a Differential ECL/PECL Clock Source
7.3.14 LVDS Inputs
The D[15:0]P/N, DATACLKP/N, SYNCP/N, PARITYP/N, and FRAMEP/N LVDS pairs have the input configuration
shown in Figure 81. Figure 82 shows the typical input levels and common-move voltage used to drive these
inputs.
IOVDD
100 Ω
LVDS
Receiver
Internal Digital In
GND
S0516-01
Figure 81. D[15:0]P/N, DATACLKP/N, FRAMEP/N, SYNCP/N and PARITYP/N LVDS Input Configuration
Example
DAC3484
VA, B
VCOM = (VA + VB)/2
VA
1.4 V
VB
1V
LVDS
Receiver
100 •
400 mV
VA, B
VA
0V
–400 mV
VB
GND
Logical Bit
Equivalent
1
0
B0459-03
Figure 82. LVDS Data Input Levels
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Table 9. Example LVDS Data Input Levels
APPLIED VOLTAGES
RESULTING
DIFFERENTIAL
VOLTAGE
RESULTING COMMONMODE VOLTAGE
VCOM
VA
VB
VA,B
1.4 V
1.0 V
400 mV
1.0 V
1.4 V
-400 mV
1.2 V
0.8 V
400 mV
0.8 V
1.2 V
-400 mV
1.2 V
1.0 V
LOGICAL BIT
BINARY
EQUIVALENT
1
0
1
0
7.3.15 Unused LVDS Port Termination
Depending on the DAC3484 functionality required, additional unused LVDS ports such as FRAMEP/N,
SYNCP/N, or PARITYP/N can be left unconnected (floating) or connected to a nominal, differential LVDS active
HIGH or active LOW voltage. The usage of these ports depends mainly on the FIFO synchronization settings and
parity checking settings. The unused FRAMEP/N, SYNCP/N, or PARITYP/N ports can be connected in parallel
with the unused LVDS data port with adjustments to the RSET resistor value.
The following example allows the termination of the unused LVDS ports to a known logic HIGH value. As shown
in Figure 83, The design involves the connection to the DIGVDD rail and one RSET resistor to bias the positive
terminals of unused LVDS ports to be 1.2 V and negative terminals of unused LVDS ports to 1.0 V. The design
keeps the minimum common mode input voltage of the LVDS input to be above 1.0 V, and keeps the differential
LVDS voltage to be 200 mV. Since the design expects the differential voltage on the unused ports to be static,
the differential LVDS voltage can be as low as 100 mV to maintain a logic HIGH. Refer to Electrical
Characteristic – Digital Specifications Table for detail of LVDS Input requirements.
DIGVDD
(1.2V Nominal)
LVDS P Terminals
(Parallel by M)
REQ or
ZT/M
LVDS N Terminals
(Parallel by M)
x
x
x
RSET
M Unused LVDS Ports Connected in Parallel.
Keep Positive Terminals at 1.2V.
Keep Static Differential Voltages above 100mV.
Figure 83. Unused LVDS Ports Connected to Static Logic High Differential Voltage
1. Connect the positive terminals of unused LVDS ports in parallel to DIGVDD supply at 1.2 V nominal. For
instance, connect SYNC and PARITY positive pins together to DIGVDD.
2. Connect the negative terminals of unused LVDS ports in parallel to a RSET resistor to ground.
3. The REQ value is the equivalent, parallel resistance of the on-chip termination for all the unused LVDS ports.
With the SYNC and PARITY ports unused, the REQ is two parallel ZT. Worst case ZT value of 135 Ω is used
in the design to account for the lowest possible current IEQ and the worst case common mode on the
negative LVDS terminals. Another analysis will be performed with ZT value of 85 Ω for worst case differential
LVDS voltages.
4. With Ohm’s Law, the following equation describes the relationship between RSET and REQ.
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RSET
RSET REQ
RSET
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1.0
1.2
4.988REQ
(2)
5. With REQ of two parallel, 135 Ω ZT (or 67.5 Ω equivalent), RSET is 332 Ω with standard 1% resistor value. IEQ
is approximately 3 mA. The expected voltage at negative terminals of LVDS ports is approximately 1.0 V.
The differential LVDS voltage is 200 mV.
6. With same RSET of 332 Ω, if the REQ has dropped to two parallel, 85 Ω ZT (or 42.5 Ω equivalent), IEQ is
approximately 3.2 mA. The expected voltage at negative terminals of LVDS port is approximately 1.06 V. The
differential LVDS voltage is 136 mV. As long as the static LVDS differential voltage is above 100 mV, the
LVDS port will register a logic HIGH value for the data.
7.3.16 CMOS Digital Inputs
Figure 84 shows a schematic of the equivalent CMOS digital inputs of the DAC3484. SDIO, SCLK, SLEEP and
TXENABLE have pull-down resistors while SDENB and RESETB have pull-up resistors internal to the DAC3484.
See the specification table for logic thresholds. The pull-up and pull-down circuitry is approximately equivalent to
100kΩ.
IOVDD
IOVDD
100 kΩ
SDIO
SCLK
SLEEP
TXENABLE
100 kΩ
400 Ω
Internal
Digital In
400 Ω
SDENB
RESETB
GND
Internal
Digital In
GND
S0027-03
Figure 84. CMOS Digital Equivalent Input
7.3.17 Reference Operation
The DAC3484 uses a bandgap reference and control amplifier for biasing the full-scale output current. The fullscale output current is set by applying an external resistor RBIAS to pin BIASJ. The bias current IBIAS through
resistor RBIAS is defined by the on-chip bandgap reference voltage and control amplifier. The default full-scale
output current equals 64 times this bias current and can thus be expressed as:
IOUTFS = 64 x IBIAS = 64 x (VEXTIO / RBIAS ) / 2
The DAC3484 has a 4-bit coarse gain control coarse_dac(3:0) in the config3 register. Using gain control, the
IOUTFS can be expressed as:
IOUTFS = (coarse_dac + 1)/16 x IBIAS x 64 = (coarse_dac + 1)/16 x (VEXTIO / RBIAS) / 2 x 64
where VEXTIO is the voltage at terminal EXTIO. The bandgap reference voltage delivers an accurate voltage of
1.2 V. This reference is active when extref_ena = 0b in config27. An external decoupling capacitor CEXT of 0.1 µF
should be connected externally to terminal EXTIO for compensation. The bandgap reference can additionally be
used for external reference operation. In that case, an external buffer with high impedance input should be
applied in order to limit the bandgap load current to a maximum of 100 nA. The internal reference can be
disabled and overridden by an external reference by setting the extref_ena control bit. Capacitor CEXT may hence
be omitted. Terminal EXTIO thus serves as either input or output node.
The full-scale output current can be adjusted from 30 mA down to 10 mA by varying resistor RBIAS or changing
the externally applied reference voltage.
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NOTE
With internal reference, the minimum Rbias resistor value is 1.28 kΩ. Resistor value below
1.28 kΩ is not recommended since it will program the full-scale current to go above 30mA
and potentially damages the device.
7.3.18 DAC Transfer Function
The CMOS DACs consist of a segmented array of PMOS current sources, capable of sourcing a full-scale output
current up to 30 mA. Differential current switches direct the current to either one of the complementary output
nodes IOUTP or IOUTN. Complementary output currents enable differential operation, thus canceling out
common mode noise sources (digital feed-through, on-chip and PCB noise), dc offsets, even order distortion
components, and increasing signal output power by a factor of two.
The full-scale output current is set using external resistor RBIAS in combination with an on-chip bandgap voltage
reference source (+1.2 V) and control amplifier. Current IBIAS through resistor RBIAS is mirrored internally to
provide a maximum full-scale output current equal to 64 times IBIAS.
The relation between IOUTP and IOUTN can be expressed as:
IOUTFS = IOUTP + IOUTN
We will denote current flowing into a node as – current and current flowing out of a node as + current. Since the
output stage is a current source the current flows from the IOUTP and IOUTN pins. The output current flow in
each pin driving a resistive load can be expressed as:
IOUTP = IOUTFS x CODE / 65536
IOUTN = IOUTFS x (65535 – CODE) / 65536
where CODE is the decimal representation of the DAC data input word
For the case where IOUTP and IOUTN drive resistor loads RL directly, this translates into single ended voltages
at IOUTP and IOUTN:
VOUTP = IOUT1 x RL
VOUTN = IOUT2 x RL
Assuming that the data is full scale (65535 in offset binary notation) and the RL is 25 Ω, the differential voltage
between pins IOUTP and IOUTN can be expressed as:
VOUTP = 20mA x 25 Ω = 0.5 V
VOUTN = 0mA x 25 Ω = 0 V
VDIFF = VOUTP – VOUTN = 0.5V
Note that care should be taken not to exceed the compliance voltages at node IOUTP and IOUTN, which would
lead to increased signal distortion.
7.3.19 Analog Current Outputs
The DAC3484 can be easily configured to drive a doubly terminated 50-Ω cable using a properly selected RF
transformer. Figure 85 and Figure 86 show the 50-Ω doubly terminated transformer configuration with 1:1 and 4:1
impedance ratio, respectively. Note that the center tap of the primary input of the transformer has to be grounded
to enable a DC current flow. Applying a 20-mA full-scale output current would lead to a 0.5 Vpp for a 1:1
transformer and a 1 Vpp output for a 4:1 transformer. The low dc-impedance between IOUTP or IOUTN and the
transformer center tap sets the center of the ac-signal to GND, so the 1 Vpp output for the 4:1 transformer
results in an output between –0.5 V and 0.5 V.
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50 Ω
1:1
IOUTP
100 Ω
RLOAD
50 Ω
AGND
IOUTN
50 Ω
S0517-01
Figure 85. Driving a Doubly terminated 50-Ω Cable Using a 1:1 Impedance Ratio Transformer
100 Ω
4:1
IOUTP
AGND
RLOAD
50 Ω
IOUTN
100 Ω
S0518-01
Figure 86. Driving a Doubly Terminated 50-Ω Cable Using a 4:1 Impedance Ratio Transformer
7.4 Device Functional Modes
7.4.1 Multi-Device Synchronization
In various applications, such as multi antenna systems where the various transmit channels information is
correlated, it is required that multiple DAC devices are completely synchronized such that their outputs are phase
aligned. The DAC3484 architecture supports this mode of operation.
7.4.1.1 Multi-Device Synchronization: PLL Bypassed with Dual Sync Sources Mode
For single or multi-device synchronization it is important that delay differences in the data are absorbed by the
device so that latency through the device remains the same. Furthermore, to guarantee that the outputs from
each DAC are phase aligned it is necessary that data is read from the FIFO of each device simultaneously. In
the DAC3484 this is accomplished by operating the multiple devices in Dual Sync Sources mode. In this mode
the additional OSTR signal is required by each DAC3484 to be synchronized.
Data into the device is input as LVDS signals from one or multiple baseband ASICs or FPGAs. Data into the
multiple DAC devices can experience different delays due to variations in the digital source output paths or board
level wiring. These different delays can be effectively absorbed by the DAC3484 FIFO so that all outputs are
phase aligned correctly.
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Device Functional Modes (continued)
DACCLKP/N
OSTRP/N
D[15:0]P/N
FPGA
DAC3484 DAC1
FRAMEP/N
Clock Generator
PLL/
DLL
LVDS Interface
LVPECL Outputs
Delay 1
DATACLKP/N
Outputs are
Phase Aligned
Variable delays due to variations in the FPGA(s) output
paths or board level wiring or temperature/voltage deltas
D[15:0]P/N
LVPECL Outputs
FRAMEP/N
DATACLKP/N
Delay 2
DAC3484 DAC2
OSTRP/N
DACCLKP/N
B0454-03
Figure 87. SynchronizationSystem in Dual Sync Sources Mode with PLL Bypassed
For correct operation both OSTR and DACCLK must be generated from the same clock domain. The OSTR
signal is sampled by DACCLK and must satisfy the timing requirements in the specifications table. If the clock
generator does not have the ability to delay the DACCLK to meet the OSTR timing requirement, the polarity of
the DACCLK outputs can be swapped with respect to the OSTR ones to create 180 degree phase delay of the
DACCLK. This may help establish proper setup and hold time requirement of the OSTR signal.
Careful board layout planning must be done to ensure that the DACCLK and OSTR signals are distributed from
device to device with the lowest skew possible as this will affect the synchronization process. In order to
minimize the skew across devices it is recommended to use the same clock distribution device to provide the
DACCLK and OSTR signals to all the DAC devices in the system.
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LVPECL Pairs (DAC3484 1)
Device Functional Modes (continued)
DACCLKP/N(1)
tS(OSTR)
tH(OSTR)
tSKEW ~ 0
LVPECL Pairs (DAC3484 2)
OSTRP/N(1)
DACCLKP/N(2)
tS(OSTR)
tH(OSTR)
OSTRP/N(2)
•
•
•
•
T0526-03
Figure 88. Timing Diagram for LVPECL Synchronization Signals
The following steps are required to ensure the devices are fully synchronized. The procedure assumes all the
DAC3484 devices have a DACCLK and OSTR signal and must be carried out on each device.
1. Start-up the device as described in the power-up sequence. Set the DAC3484 in Dual Sync Sources mode
and select OSTR as the clock divider sync source (clkdiv_sync_sel in register config32).
2. Sync the clock divider and FIFO pointers.
3. Verify there are no FIFO alarms either through register config5 or through the ALARM pin.
4. Disable clock divider sync by setting clkdiv_sync_ena to 0b in register config0.
After these steps all the DAC3484 outputs will be synchronized.
7.4.1.2 Multi-Device Synchronization: PLL Enabled with Dual Sync Sources Mode
The DAC3484 allows exact phase alignment between multiple devices even when operating with the internal PLL
clock multiplier. In PLL clock mode, the PLL generates the DAC clock and an internal OSTR signal from the
reference clock applied to the DACCLK inputs so there is no need to supply an additional LVPECL OSTR signal.
For this method to operate properly the SYNC signal should be set to reset the PLL N dividers to a known state
by setting pll_ndivsync_ena in register config24 to 1b. The SYNC signal resets the PLL N dividers with a rising
edge, and the timing relationship ts(SYNC_PLL) and th(SYNC_PLL) are relative to the reference clock presented on the
DACCLK pin.
Both SYNC and DACCLK can be set as low frequency signals to greatly simplifying trace routing (SYNC can be
just a pulse as a single rising edge is required, if using a periodic signal it is recommended to clear the
pll_ndivsync_ena bit after resetting the PLL dividers). Besides the ts(SYNC_PLL) and th(SYNC_PLL) requirement
between SYNC and DACCLK, there is no additional required timing relationship between the SYNC and FRAME
signals or between DACCLK and DATACLK. The only restriction as in the PLL disabled case is that the DACCLK
and SYNC signals are distributed from device to device with the lowest skew possible.
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Device Functional Modes (continued)
DACCLKP/N
SYNCP/N
D[15:0]P/N
FPGA
DAC3484 DAC1
FRAMEP/N
Clock Generator
PLL/
DLL
LVDS Interface
Outputs
Delay 1
DATACLKP/N
Outputs are
Phase Aligned
Variable delays due to variations in the FPGA(s) output
paths or board level wiring or temperature/voltage deltas
D[15:0]P/N
Outputs
FRAMEP/N
DATACLKP/N
Delay 2
DAC3484 DAC2
SYNCP/N
DACCLKP/N
B0455-03
Figure 89. Synchronization System in Dual Sync Sources Mode with PLL Enabled
The following steps are required to ensure the devices are fully synchronized. The procedure assumes all the
DAC3484 devices have a DACCLK and SYNC signal and the following steps must be carried out on each
device.
1. Start-up the device as described in the power-up sequence. Set the DAC3484 in Dual Sync Sources mode
and enable SYNC to reset the PLL dividers (set pll_ndivsync_ena in register config24 to 1b).
2. Reset the PLL dividers with a rising edge on SYNC.
3. Disable PLL dividers resetting.
4. Sync the clock divider and FIFO pointers.
5. Verify there are no FIFO alarms either through register config5 or through the ALARM pin.
6. Disable clock divider sync by setting clkdiv_sync_ena to 0b in register config0.
After these steps all the DAC3484 outputs will be synchronized.
7.4.1.3 Multi-Device Operation: Single Sync Source Mode
In Single Sync Source mode the FIFO read pointer reset is handoff between the two clock domains (DATACLK
and FIFO OUT CLOCK) by simply re-sampling the write pointer reset. Since the two clocks are asynchronous
there is a small but distinct possibility of a meta-stability during the pointer handoff. As described in the Input
FIFO section, this meta-stable situation can change the latency of the multiple DAC devices by both the FIFO
Out clock cycles and DAC clock cycles.
When the PLL is enabled with Single Sync Source mode, the FIFO read pointer is not synchronized by the
OSTR signal. Therefore, there is no restriction on the PLL PFD frequency as described in the previous section.
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Device Functional Modes (continued)
DACCLKP/N
D[15:0]P/N
FPGA
DAC3484 DAC1
FRAMEP/N
Clock Generator
PLL/
DLL
LVDS Interface
LVPECL Outputs
Delay 1
DATACLKP/N
Variable delays due to variations in the FPGA(s) output
paths or board level wiring or temperature/voltage deltas
D[15:0]P/N
Variation in both the FIFO
Out clock cycles and DAC
clock cycles
LVPECL Outputs
FRAMEP/N
DATACLKP/N
Delay 2
DAC3484 DAC2
DACCLKP/N
B0456-03
Figure 90. Multi-Device Operation in Single Sync Source Mode
7.5 Programming
7.5.1 Power-Up Sequence
The following startup sequence is recommended to power-up the DAC3484:
1. Set TXENABLE low
2. Supply all 1.2-V voltages (DACVDD, DIGVDD, CLKVDD, and VFUSE) and all 3.3-V voltages (AVDD,
IOVDD, and PLLAVDD). The 1.2-V and 3.3-V supplies can be powered up simultaneously or in any order.
There are no specific requirements on the ramp rate for the supplies.
3. Provide all LVPECL inputs: DACCLKP/N and the optional OSTRP/N. These inputs can also be provided after
the SIF register programming.
4. Toggle the RESETB pin for a minimum 25 ns active low pulse width.
5. Program the SIF registers.
6. Program fuse_sleep (config27, bit<11>) to put the internal fuses to sleep. To enable dual channel mode, set
Config1, bit <8> to 0b and Config16, bit<13:12> to 11b. This dual channel mode is functionally equivalent to
the dual channel DAC3484 (channels B and C active). See the DAC3484 SLAS748 datasheet for details.
7. FIFO configuration needed for synchronization:
(a) Program syncsel_fifoin(3:0) (config32, bits<15:12>) to select the FIFO input pointer sync source.
(b) Program syncsel_fifoout(3:0) (config32, bits<11:8>) to select the FIFO output pointer sync source.
(c) Program syncsel_dataformatter(1:0) (config31, bits<3:2>) to select the FIFO Data Formatter sync source.
8. Clock divider configuration needed for synchronization:
(a) Program clkdiv_sync_sel (config32, bit<0>) to select the clock divider sync source.
(b) Program clkdiv_sync_ena (config0, bit<2>) to 1b to enable clock divider sync.
(c) For multi-DAC synchronization in PLL mode, program pll_ndivsync_ena (config24, bit<11>) to 1b to
synchronize the PLL N-divider.
9. Provide all LVDS inputs (D[15:0]P/N, DATACLKP/N, FRAMEP/N, SYNCP/N, and PARITYP/N)
simultaneously. Synchronize the FIFO and clock divider by providing the pulse or periodic signals needed.
(a) For Single Sync Source Mode where either FRAMEP/N or SYNCP/N is used to sync the FIFO, a single
rising edge for FIFO, FIFO data formatter, and clock divider sync is recommended. Periodic sync signal
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Programming (continued)
is not recommended due to the non-deterministic latency of the sync signal through the clock domain
transfer.
(b) For Dual Sync Sources Mode, both single pulse or periodic sync signals can be used.
(c) For multi-DAC synchronization in PLL mode, the LVDS SYNCP/N signal is used to sync the PLL Ndivider and can be sourced from either the FPGA/ASIC pattern generator or clock distribution circuit as
long as the t(SYNC_PLL) setup and hold timing requirement is met with respect to the reference clock
source at DACCLKP/N pins. The LVDS SYNCP/N signal can be provided at this point.
10. FIFO and clock divider configurations after all the sync signals have provided the initial sync pulses needed
for synchronization:
(a) For Single Sync Source Mode where the clock divider sync source is either FRAMEP/N or SYNCP/N,
clock divider syncing may be disabled after DAC3484 initialization and before the data transmission by
setting clkdiv_sync_ena (config0, bit <2>) to 0b. This is to prevent accidental syncing of the clock divider
when sending FRAMEP/N or SYNCP/N pulse to other digital blocks.
(b) For Dual Sync Sources Mode, where the clock divider sync source is from the OSTR signal (either from
external OSTRP/N or internal PLL N divider output), the clock divider syncing may be enabled at all time.
(c) Optionally, to prevent accidental syncing of the FIFO and FIFO data formatter when sending the
FRAMEP/N or SYNCP/N pulse to other digital blocks such as NCO, QMC, etc, disable FIFO syncing by
setting syncsel_fifoin(3:0) and syncsel_fifoout(3:0) to 0000b after the FIFO input and output pointers are
initialized. Also Disable the FIFO data formatter by setting syncsel_dataformatter(1:0) to 10b or 11b. If
the FIFO and FIFO data formatter sync remain enabled after initialization, the FRAMEP/N or SYNCP/N
pulse must occur in ways to not disturb the FIFO operation. Refer to the INPUT FIFO section for detail.
(d) Disable PLL N-divider syncing by setting pll_ndivsync_ena (config24, bit<11>) to 0b.
11. Enable transmit of data by asserting the TXENABLE pin or set sif_txenable to 1b.
12. At any time, if any of the clocks (i.e DATACLK or DACCLK) is lost or a FIFO collision alarm is detected, a
complete resynchronization of the DAC is necessary. Set TXENABLE low and repeat steps 7 through 11.
Program the FIFO configuration and clock divider configuration per steps 7 and 8 appropriately to accept the
new sync pulse or pulses for the synchronization.
7.5.2 Example Start-Up Routine
7.5.2.1 Device Configuration
fDATA = 307.2 MSPS
Interpolation = 4x
Input data = baseband data
fOUT = 122.88 MHz
PLL = Enabled
Full Mixer = Enabled
Dual Sync Sources Mode
7.5.2.2 PLL Configuration
fREFCLK = 614.4 MHz at the DACCLKP/N LVPECL pins
fDACCLK = fDATA x Interpolation = 1228.8 MHz
fVCO = 3 x fDACCLK = 3686.4 MHz (keep fVCO between 3.3 GHz to 4 GHz)
PFD = fOSTR = 38.4 MHz
N = 16, M = 32, P = 3, single charge pump
pll_vco(5:0) = 100100b (36)
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Programming (continued)
7.5.2.3 NCO Configuration
fNCO = 122.88 MHz
fNCO_CLK = 1228.8 MHz
freq = fNCO x 2^32 / 1228.8 = 429496730 = 0x1999999A
phaseaddAB(31:0) or phaseaddCD(31:0) = 0x19999999A
NCO SYNC = rising edge of SYNC
7.5.2.4 Example Start-Up Sequence
Table 10. Example Start-Up Sequence Description
64
STEP
READ/WRITE
ADDRESS
VALUE
1
N/A
N/A
N/A
Set TXENABLE Low
DESCRIPTION
2
N/A
N/A
N/A
Power-up the device
3
N/A
N/A
N/A
Apply LVPECL DACCLKP/N for PLL reference clock
4
N/A
N/A
N/A
Toggle RESETB pin
5
Write
0x00
0xF29F
QMC offset and correction enabled, 4x int, FIFO enabled, Alarm enabled,
clock divider sync enabled, inverse sinc filter enabled.
6
Write
0x01
0x050E
Single parity enabled, FIFO alarms enabled (2 away, 1 away, and collision).
7
Write
0x02
0xF052
Output shut-off when DACCLK gone, DATACLK gone, and FIFO collision.
Mixer block with NCO enabled, twos complement. Word Wide Interface.
8
Write
0x03
0xA000
Output current set to 20mAFS with internal reference and 1.28-kΩ RBIAS
resistor.
9
Write
0x07
0xD8FF
Un-mask FIFO collision, DACCLK-gone, and DATACLK-gone alarms to the
Alarm output.
10
Write
0x08
N/A
Program the desired channel A QMC offset value. (Causes Auto-Sync for
QMC AB-Channels Offset Block)
11
Write
0x09
N/A
Program the desired FIFO offset value and channel B QMC offset value.
12
Write
0x0A
N/A
Program the desired channel C QMC offset value. (Causes Auto-Sync for
QMC CD-Channels Offset Block)
13
Write
0x0B
N/A
Program the desired channel D QMC offset value.
14
Write
0x0C
N/A
Program the desired channel A QMC gain value.
15
Write
0x0D
N/A
Coarse mixer mode not used. Program the desired channel B QMC gain
value.
16
Write
0x0E
N/A
Program the desired channel C QMC gain value.
17
Write
0x0F
N/A
Program the desired channel D QMC gain value.
18
Write
0x10
N/A
Program the desired channel AB QMC phase value. (Causes Auto-Sync
QMC AB-Channels Correction Block)
19
Write
0x11
N/A
Program the desired channel CD QMC phase value. (Causes Auto-Sync for
the QMC CD-Channels Correction Block)
20
Write
0x12
N/A
Program the desired channel AB NCO phase offset value. (Causes AutoSync for Channel AB NCO Mixer)
21
Write
0x13
N/A
Program the desired channel CD NCO phase offset value. (Causes AutoSync for Channel CD NCO Mixer)
22
Write
0x14
0x999A
Program the desired channel AB NCO frequency value
23
Write
0x15
0x1999
Program the desired channel AB NCO frequency value
24
Write
0x16
0x999A
Program the desired channel CD NCO frequency value
25
Write
0x17
0x1999
Program the desired channel CD NCO frequency value
26
Write
0x18
0x2C58
PLL enabled, PLL N-dividers sync enabled, single charge pump, prescaler =
3.
27
Write
0x19
0x20F4
M = 32, N = 16, PLL VCO bias tune = 01b
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Programming (continued)
Table 10. Example Start-Up Sequence Description (continued)
STEP
READ/WRITE
ADDRESS
VALUE
28
Write
0x1A
0x9000
PLL VCO coarse tune = 36
DESCRIPTION
29
Write
0x1B
0x0800
Internal reference
30
Write
0x1E
0x9999
QMC offset AB, QMC offset CD, QMC correction AB, and QMC correction
CD can be synced by sif_sync or auto-sync from register write
31
Write
0x1F
0x4440
Mixer AB and CD values synced by SYNCP/N. NCO accumulator synced by
SYNCP/N.
32
Write
0x20
0x2400
FIFO Input Pointer Sync Source = ISTR FIFO Output Pointer Sync Source =
OSTR (from PLL N-divider output) Clock Divider Sync Source = OSTR
33
N/A
N/A
N/A
Provide all the LVDS DATA and DATACLK Provide rising edge FRAMEP/N
and rising edge SYNCP/N to sync the FIFO input pointer and PLL Ndividers.
34
Read
0x18
N/A
Read back pll_lfvolt(2:0). If the value is not optimal, adjust pll_vco(5:0) in
0x1A.
35
Write
0x05
0x0000
36
Read
0x05
N/A
37
Write
0x1F
0x4442
Sync all the QMC blocks using sif_sync. These blocks can also be synced
via auto-sync through appropriate register writes.
38
Write
0x00
0xF29B
Disable clock divider sync.
39
Write
0x1F
0x4448
Set sif_sync to 0b for the next sif_sync event.
40
Write
0x20
0x0000
Disable FIFO input and output pointer sync.
41
Write
0x18
0x2458
Disable PLL N-dividers sync.
42
N/A
N/A
N/A
Clear all alarms in 0x05.
Read back all alarms in 0x05. Check for PLL lock, FIFO collision, DACCLKgone, DATACLK-gone, etc. Fix the error appropriately. Repeat step 34 and
35 as necessary.
Set TXENABLE high. Enable data transmission.
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7.6 Register Map
Table 11. Register Map (1)
Name
Address
Default
(MSB)
Bit 15
Bit 14
Bit 13
Bit 12
config0
0x00
0x049C
qmc_
offsetAB_
ena
qmc_
offsetCD_
ena
qmc_
corrAB_
ena
qmc_
corrCD_
ena
config1
0x01
0x050E
iotest_ena
reserved
reserved
64cnt_
ena
oddeven_
parity
word_
parity_
ena
frame_
parity_
ena
config2
0x02
0x7000
16bit_in
dacclk
gone_ena
dataclk
gone_ena
collision_
gone_ena
reserved
reserved
reserved
config3
0x03
0xF000
config4
0x04
NA
config5
0x05
0x0000
config6
0x06
NA
config7
0x07
0xFFFF
config8
0x08
0x0000
config9
0x09
0x8000
config10
0x0A
0x0000
reserved
config11
0x0B
0x0000
config12
0x0C
0x0400
config13
0x0D
0x0400
config14
0x0E
0x0400
config15
0x0F
0x0400
output_delayAB (1:0)
config16
0x10
0x0000
reserved
reserved
config17
0x11
0x0000
reserved
reserved
config18
0x12
0x0000
phase_offsetAB(15:0)
config19
0x13
0x0000
phase_offsetCD(15:0)
config20
0x14
0x0000
phase_addAB(15:0)
config21
0x15
0x0000
phase_addAB(31:16)
config22
0x16
0x0000
phase_addCD(15:0)
config23
0x17
0x0000
phase_addCD(31:16)
config24
0x18
NA
config25
0x19
0x0440
config26
0x1A
0x0020
config27
0x1B
0x0000
(1)
66
Bit 11
Bit 10
Bit 9
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
(LSB)
Bit 0
fifo_ena
reserved
reserved
alarm_out_
ena
alarm_out
pol
clkdiv_
sync_ ena
invsincAB_
ena
invsincCD_
ena
quad_ena
dacA_
complement
dacB_
complement
dacC_
complement
dacD_
complement
alarm_
2away_
ena
alarm_
1away_
ena
alarm_
collision_
ena
reserved
reserved
sif4_ena
mixer_ena
mixer_gain
nco_ena
revbus
reserved
twos
reserved
Bit 8
interp(3:0)
coarse_dac(3:0)
reserved
reserved
sif_txenable
iotest_results(15:0)
alarm_
from_
zerochk
reserved
alarms_from_fifo(2:0)
alarm_
dacclk_
gone
alarm_
dataclk_
gone
alarm_
from_
iotest
alarm_
output_
gone
reserved
alarm_
from_pll
tempdata(7:0)
alarm_
rparity
alarm_
fparity
alarm_
frame_
parity
reserved
reserved
reserved
reserved
reserved
alarms_mask(15:0)
reserved
reserved
reserved
qmc_offsetA(12:0)
reserved
reserved
qmc_offsetC(12:0)
reserved
reserved
reserved
reserved
reserved
reserved
fifo_offset(2:0)
qmc_offsetB(12:0)
qmc_offsetD(12:0)
reserved
cmix(3:0)
reserved
reserved
reserved
qmc_gainA(10:0)
reserved
qmc_gainB(10:0)
reserved
reserved
qmc_gainC(10:0)
output_delayCD (1:0)
reserved
reserved
qmc_gainD(10:0)
dual_ena (1:0)
reserved
reserved
qmc_phaseAB(11:0)
reserved
pll_reset
qmc_phaseCD(11:0)
pll_
ndivsync_
ena
pll_ena
reserved
pll_cp(1:0)
pll_m(7:0)
pll_n(3:0)
pll_vco(5:0)
extref_
ena
reserved
reserved
reserved
fuse_
sleep
pll_p(2:0)
reserved
reserved
reserved
bias_
sleep
reserved
reserved
reserved
tsense_
sleep
reserved
pll_sleep
pll_lfvolt(2:0)
pll_vcoitune(2:0)
clkrecv_
sleep
sleepA
sleepB
reserved
sleepC
sleepD
reserved
Unless otherwise noted, all reserved registers should be programmed to default values.
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Register Map (continued)
Table 11. Register Map(1) (continued)
(MSB)
Bit 15
Name
Address
Default
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
config28
0x1C
0x0000
reserved
config29
0x1D
0x0000
reserved
config30
0x1E
0x1111
syncsel_qmoffsetAB(3:0)
syncsel_qmoffsetCD(3:0)
syncsel_qmcorrAB(3:0)
config31
0x1F
0x1140
syncsel_mixerAB(3:0)
syncsel_mixerCD(3:0)
syncsel_nco(3:0)
config32
0x20
0x2400
syncsel_fifoin(3:0)
syncsel_fifoout(3:0)
config33
0x21
0x0000
config34
0x22
0x1B1B
config35
0x23
0xFFFF
config36
0x24
0x0000
config37
0x25
0x7A7A
iotest_pattern0
config38
0x26
0xB6B6
iotest_pattern1
config39
0x27
0xEAEA
iotest_pattern2
config40
0x28
0x4545
iotest_pattern3
config41
0x29
0x1A1A
iotest_pattern4
config42
0x2A
0x1616
iotest_pattern5
config43
0x2B
0xAAAA
iotest_pattern6
config44
0x2C
0xC6C6
Bit 3
Bit 2
(LSB)
Bit 0
Bit 1
reserved
reserved
syncsel_qmcorCD(3:0)
syncsel_dataformatter
sif_sync
reserved
clkdiv_
sync_sel
reserved
reserved
pathA_in_sel(1:0)
pathB_in_sel(1:0)
pathC_in_sel(1:0)
pathD_in_sel(1:0)
DACA_out_sel(1:0)
DACB_out_sel(1:0)
DACC_out_sel(1:0)
DACD_out_sel(1:0)
sleep_cntl(15:0)
datadly(2:0)
clkdly(2:0)
reserved
iotest_pattern7
reserved
ostrtodig_
sel
config45
0x2D
0x0004
config46
0x2E
0x0000
ramp_ena
grp_delayA(7:0)
reserved
config47
0x2F
0x0000
grp_delayC(7:0)
config48
0x30
0x0000
version
0x7F
0x540C
sifdac_ena
grp_delayB(7:0)
grp_delayD(7:0)
sifdac(15:0)
reserved
reserved
reserved
reserved
deviceid(1:0)
versionid(2:0)
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7.6.1 Register Descriptions
Table 12. Register Name: config0 – Address: 0x00, Default: 0x049C
Register
Name
Address
Bit
Name
Function
config0
0x00
15
qmc_offsetAB_ena
When set, the digital Quadrature Modulator Correction (QMC) offset
correction for the AB data path is enabled.
0
14
qmc_offsetCD_ena When set, the digital Quadrature Modulator Correction (QMC) offset
correction for the CD data path is enabled.
0
13
qmc_corrAB_ena
When set, the QMC phase and gain correction circuitry for the AB
data path is enabled.
0
12
qmc_corrCD_ena
When set, the QMC phase and gain correction circuitry for the CD
data path is enabled.
0
interp(3:0)
These bits define the interpolation factor
11:8
68
Default
Value
0100
interp
Interpolation Factor
0000
1x
0001
2x
0010
4x
0100
8x
1000
16x
7
fifo_ena
When set, the FIFO is enabled. When the FIFO is disabled,
DACCCLKP/N and DATACLKP/N must be aligned (not
recommended).
1
6
Reserved
Reserved for factory use.
0
5
Reserved
Reserved for factory use.
0
4
alarm_out_ena
When set, the ALARM pin becomes an output. When cleared, the
ALARM pin is 3-stated.
1
3
alarm_out_pol
This bit changes the polarity of the ALARM signal.
MM 0: Negative logic
MM 1: Positive logic
1
2
clkdiv_sync_ena
When set, enables the syncing of the clock divider using the sync
source selected by register config32. The internal divided-down
clocks will be phase aligned after syncing. Refer to the Power-Up
Sequence section for more detail.
1
1
invsincAB_ena
When set, the inverse sinc filter for the AB data is enabled.
0
0
invsincCD_ena
When set, the inverse sinc filter for the CD data is enabled.
0
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Table 13. Register Name: config1 – Address: 0x01, Default: 0x050E
Register
Name
Address
Bit
config1
0x01
15
iotest_ena
When set, enables the data pattern checker test. The outputs are
deactivated regardless of the state of TXENABLE and
sif_txenable.
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
0
12
64cnt_ena
When set, enables resetting of the alarms after 64 good samples
with the goal of removing unnecessary errors. For instance, when
checking setup/hold through the pattern checker test, there may
initially be errors. Setting this bit removes the need for a SIF write to
clear the alarm register.
0
11
oddeven_parity
Selects between odd and even parity check
MM 0: Even parity
MM 1: Odd parity
0
10
word_parity_ena
When set, enables parity checking of each input word using the
PARITYP/N parity input. It should match the oddeven_parity
register setting.
1
9
frame_parity_ena
When set, enables parity checking using the FRAME signal to
source the parity bit.
0
8
quad_ena
When set, the device is in quad channel mode. To enable the dual
channel mode, set Config1, bit <8> to 0b and Config16, bit<13:12>
to 11b. This dual channel mode is functionally equivalent to the dual
channel DAC3484 (channels B and C active). See the DAC3484
SLAS748 datasheet for details.
1
7
dacA_complement
When set, the DACA output is complemented. This allows to
effectively change the + and – designations of the LVDS data lines.
0
6
dacB_complement
When set, the DACB output is complemented. This allows to
effectively change the + and – designations of the LVDS data lines.
0
5
dacC_complement
When set, the DACC output is complemented. This allows to
effectively change the + and – designations of the LVDS data lines.
0
4
dacD_complement
When set, the DACD output is complemented. This allows to
effectively change the + and – designations of the LVDS data lines.
0
3
alarm_2away_ena
When set, the alarm from the FIFO indicating the write and read
pointers being 2 away is enabled.
1
2
alarm_1away_ena
When set, the alarm from the FIFO indicating the write and read
pointers being 1 away is enabled.
1
1
alarm_collision_ena
When set, the alarm from the FIFO indicating a collision between the
write and read pointers is enabled.
1
0
Reserved
Reserved for factory use.
0
Name
Default
Value
Function
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Table 14. Register Name: config2 – Address: 0x02, Default: 0x7000
Register
Name
Address
Bit
config2
0x02
15
16bit_in
When set, the input interface is set to word-wide mode.
When cleared, the input interface is set to byte-wide mode.
0
14
dacclkgone_ena
When set, the DACCLK-gone signal from the clock monitor circuit can
be used to shut off the DAC outputs. The corresponding alarms,
alarm_dacclk_gone and alarm_output_gone, must not be masked
(i.e.Config7, bit <10> and bit <8> must set to 0b).
1
13
dataclkgone_ena
When set, the DATACLK-gone signal from the clock monitor circuit
can be used to shut off the DAC outputs. The corresponding alarms,
alarm_dataclk_gone and alarm_output_gone, must not be masked
(i.e.Config7, bit <9> and bit <8> must set to 0b).
1
12
collisiongone_ena
When set, the FIFO collision alarms can be used to shut off the DAC
outputs. The corresponding alarms, alarm_fifo_collision and
alarm_output_gone, must not be masked (i.e.Config7, bit <13> and
bit <8> must set to 0b).
1
11
Reserved
Reserved for factory use.
0
10
Reserved
Reserved for factory use.
0
9
Reserved
Reserved for factory use.
0
8
Reserved
Reserved for factory use.
0
7
sif4_ena
When set, the serial interface (SIF) is a 4 bit interface, otherwise it is
a 3-bit interface.
0
6
mixer_ena
When set, the mixer block is enabled.
0
5
mixer_gain
When set, a 6dB gain is added to the mixer output.
0
4
nco_ena
When set, the NCO is enabled. This is not required for coarse mixing.
0
3
revbus
When set, the input bits for the data bus are reversed. MSB becomes
LSB.
0
2
Reserved
Reserved for factory use.
0
1
twos
When set, the input data format is expected to be 2s complement.
When cleared, the input is expected to be offset-binary.
0
0
Reserved
Reserved for factory use.
0
Name
Function
Default
Value
Table 15. Register Name: config3 – Address: 0x03, Default: 0xF000
Register
Name
Address
Bit
config3
0x03
15:12
Name
coarse_dac(3:0)
Function
Scales the output current in 16 equal steps.
IFS
Default
Value
1111
V
= EXTIO ´ 2 ´ (coarse _ dac + 1)
RBIAS
11:8
Reserved
Reserved for factory use.
0000
7:1
Reserved
Reserved for factory use.
0000000
sif_txenable
When set, the internal value of TXENABLE is set to 1b.
To enable analog output data transmission, set sif_txenable to 1b or
pull CMOS TXENABLE pin (A32 for DAC3484IRKD and N9 for
DAC3484IZAY) to high. To disable analog output, set sif_txenable to
0b and pull CMOS TXENABLE pin (A32 for DAC3484IRKD and N9
for DAC3484IZAY) to low.
0
0
Table 16. Register Name: config4 – Address: 0x04, Default: No RESET Value (Write to Clear)
Register
Name
Address
Bit
config4
0x04
15:0
70
Name
iotest_results(15:0)
Function
This register is used with pattern checker test enabled (iotest_ena in config1,
bit<15> set to 1b). It does not have a default RESET value.
The values of these bits tell which bit in the word failed during the pattern
checker test. iotest_results(15:8) correspond to the data bits on D[15:8] and
iotest_results(7:0) correspond to the data bits on D[7:0].
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Default
Value
No RESET
Value
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Table 17. Register Name: config5 – Address: 0x05, Default: Setup and Power-Up Conditions Dependent
(Write to Clear)
Register
Name
Address
config5
0x05
Bit
Name
Function
Default
Value
15
alarm_from_zerochk
This alarm indicates the 8-bit FIFO write pointer address has an all
zeros patterns. Due to pointer address being a shift register, this is
not a valid address and will cause the write pointer to be stuck until
the next sync. This error is typically caused by timing error or
improper power start-up sequence. If this alarm is asserted,
resynchronization of FIFO is necessary. See Power-Up Sequence
for more detail.
NA
14
Reserved
Reserved for factory use.
NA
alarms_from_fifo(2:0)
Alarm indicating FIFO pointer collisions and nearness:
MM 000: All fine
MM 001: Pointers are 2 away
MM 01x: Pointers are 1 away
MM 1xx: FIFO pointer collision
If the FIFO pointer collision alarm is set when collisiongone_ena is
enabled, the FIFO must be re-synchronized and the bits must be
cleared to resume normal operation.
NA
10
alarm_dacclk_gone
Alarm indicating the DACCLK has been stopped. If the bit is set
when dacclkgone_ena is enabled, the DACCLK must resume and
the bit must be cleared to resume normal operation.
NA
9
alarm_dataclk_gone
Alarm indicating the DATACLK has been stopped. If the bit is set
when dataclkgone_ena is enabled, the DATACLK must resume and
the bit must be cleared to resume normal operation.
NA
8
alarm_output_gone
Alarm indicating either alarm_dacclk_gone, alarm_dataclk_gone, or
alarm_fifo_collision are asserted. It controls the output. When high it
will output 0x8000 for each output connected to the DAC. If the bit is
set when dacclkgone_ena, dataclkgone_ena, or collisiongone_ena
are enabled, then the corresponding errors must be fixed and the
bits must be cleared to resume normal operation.
NA
7
alarm_from_iotest
Alarm indicating the input data pattern does not match the pattern in
the iotest_pattern registers. When data pattern checker mode is
enabled, this alarm in register config5, bit7 is the only valid alarm.
Other alarms in register config5 are not valid and can be
disregarded.
NA
6
Reserved
Reserved for factory use.
NA
5
alarm_from_pll
Alarm indicating the PLL has lost lock. For version ID 100b or
earlier, alarm_from_PLL may not indicate the correct status of the
PLL. Refer to pll_lfvolt(2:0) in register config24 for proper PLL lock
indication.
NA
4
alarm_rparity
Alarm indicating a parity error on data captured on the rising edge
of DATACLKP/N.
NA
3
alarm_fparity
Alarm indicating a parity error on data captured on the falling edge
of DATACLKP/N.
NA
2
alarm_frame_parity
Alarm indicating a parity error when using the FRAME as parity bit.
NA
1
Reserved
Reserved for factory use.
NA
0
Reserved
Reserved for factory use.
NA
13:11
Table 18. Register Name: config6 – Address: 0x06, Default: No RESET Value (Read Only)
Register
Name
Address
Bit
config6
0x06
15:8
tempdata(7:0)
This is the output from the chip temperature sensor. The value of this register in
two’s complement format represents the temperature in degrees Celsius. This
register must be read with a minimum SCLK period of 1 μs.
No
RESET
Value
7:2
Reserved
Reserved for factory use.
000000
1
Reserved
Reserved for factory use.
0
0
Reserved
Reserved for factory use.
0
Name
Default
Value
Function
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Table 19. Register Name: config7 – Address: 0x07, Default: 0xFFFF
Register
Name
Address
Bit
config7
0x07
15:0
Name
alarms_mask(15:0)
Default
Value
Function
These bits control the masking of the alarms. (0 = not masked, 1 = masked)
alarm_mask
Alarm that is Masked
15
alarm_from_zerochk
14
not used
13
alarm_fifo_collision
12
alarm_fifo_1away
11
alarm_fifo_2away
10
alarm_dacclk_gone
9
alarm_dataclk_gone
8
alarm_output_gone
7
alarm_from_iotest
6
not used
5
alarm_from_pll
4
alarm_rparity
3
alarm_fparity
2
alarm_frame_parity
1
not used
0
not used
0xFFFF
Table 20. Register Name: config8 – Address: 0x08, Default: 0x0000 (Causes Auto-Sync)
Register
Name
Address
Bit
config8
0x08
15
Reserved
Reserved for factory use.
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
qmc_offsetA(12:0)
DACA offset correction. The offset is measured in DAC LSBs. If enabled in config30
writing to this register causes an auto-sync to be generated. This loads the values of
the QMC offset registers (config8-config9) into the offset block at the same time.
When updating the offset values for AB channel config8 should be written last.
Programming config9 will not affect the offset setting.
Name
12:0
Function
Default
Value
0
All zeros
Table 21. Register Name: config9 – Address: 0x09, Default: 0x8000
Register
Name
Address
config9
0x09
Bit
Name
Function
15:13 fifo_offset(2:0)
When the sync to the FIFO occurs, this is the value loaded into the FIFO read pointer. With
this value the initial difference between write and read pointers can be controlled. This may
be helpful in syncing multiple chips or controlling the delay through the device.
12:0
DACB offset correction. The offset is measured in DAC LSBs.
qmc_offsetB(12:0)
Default
Value
100
All zeros
Table 22. Register Name: config10 – Address: 0x0A, Default: 0x0000 (Causes Auto-Sync)
Register
Name
Address
Bit
config10
0x0A
15
Reserved
Reserved for factory use.
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
qmc_offsetC(12:0)
DACC offset correction. The offset is measured in DAC LSBs. If enabled in config30
writing to this register causes an auto-sync to be generated. This loads the values of
the CD-channel QMC offset registers (config10-config11) into the offset block at the
same time. When updating the offset values for the CD-channel config10 should be
written last. Programming config11 will not affect the offset setting.
12:0
72
Name
Function
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Default
Value
0
All zeros
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Table 23. Register Name: config11 – Address: 0x0B, Default: 0x0000
Register
Name
Address
Bit
config11
0x0B
15
Reserved
Reserved for factory use.
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
qmc_offsetD(12:0)
DACD offset correction. The offset is measured in DAC LSBs.
12:0
Name
Default
Value
Function
0
All zeros
Table 24. Register Name: config12 – Address: 0x0C, Default: 0x0400
Register
Name
Address
Bit
config12
0x0C
15
Reserved
Reserved for factory use.
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
0
12
Reserved
Reserved for factory use.
0
11
Reserved
Reserved for factory use.
qmc_gainA(10:0)
QMC gain for DACA. The full 11-bit qmc_gainA(10:0) word is formatted as UNSIGNED
with a range of 0 to 1.9990. The implied decimal point for the multiplication is between bit
9 and bit 10.
10:0
Name
Default
Value
Function
0
10000000
000
Table 25. Register Name: config13 – Address: 0x0D, Default: 0x0400
Register
Name
Address
Bit
config13
0x0D
15
cmix_mode(3:0)
Sets the mixing function of the coarse mixer.
MM Bit 15: Fs/8 mixer
MM Bit 14: Fs/4 mixer
MM Bit 13: Fs/2 mixer
MM Bit 12: -Fs/4 mixer
The various mixers can be combined together to obtain a ±n×Fs/8 total mixing factor.
11
Reserved
Reserved for factory use.
qmc_gainB(10:0)
QMC gain for DACB. The full 11-bit qmc_gainB(10:0) word is formatted as UNSIGNED
with a range of 0 to 1.9990. The implied decimal point for the multiplication is between
bit 9 and bit 10.
10:0
Name
Default
Value
Function
0000
0
10000000
000
Table 26. Register Name: config14 – Address: 0x0E, Default: 0x0400
Register
Name
Address
Bit
config14
0x0E
15
Reserved
Reserved for factory use.
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
0
12
Reserved
Reserved for factory use.
0
11
Reserved
Reserved for factory use.
qmc_gainC(10:0)
QMC gain for DACC. The 11-bit qmc_gainC(10:0) word is formatted as UNSIGNED
with a range of 0 to 1.9990. The implied decimal point for the multiplication is between
bit 9 and bit 10.
10:0
Name
Default
Value
Function
0
10000000
000
Table 27. Register Name: config15 – Address: 0x0F, Default: 0x0400
Register
Name
Address
Bit
config15
0x0F
15:14
output_
delayAB(1:0)
Delays the AB data path outputs from 0 to 3 DAC clock cycles.
00
13:12
output_
delayCD(1:0)
Delays the CD data path outputs from 0 to 3 DAC clock cycles.
00
Reserved
Reserved for factory use.
qmc_gainD(10:0)
QMC gain for DACD. The full 11-bit qmc_gainD(10:0) word is formatted as UNSIGNED
with a range of 0 to 1.9990. The implied decimal point for the multiplication is between
bit 9 and bit 10.
11
10:0
Name
Default
Value
Function
0
10000000
000
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Table 28. Register Name: config16 – Address: 0x10, Default: 0x0000 (Causes Auto-Sync)
Register
Name
Address
Bit
config16
0x10
15
Reserved
Reserved for factory use.
0
14
Reserved
Reserved for factory use.
0
13:12
dual_ena (1:0)
To enable the dual channel mode, set Config1, bit <8> to 0b and Config16,
bit<13:12> to 11b. This dual channel mode is functionally equivalent to the dual
channel DAC3484 (channels B and C active). See the DAC3482 SLAS748 data
sheet for details.
0
11:0
qmc_phaseAB(11:0)
QMC correction phase for the AB data path. The 12-bit qmc_phaseAB(11:0) word is
formatted as 2s complement and scaled to occupy a range of –0.5 to 0.49975 and a
default phase correction of 0.00. To accomplish QMC phase correction, this value is
multiplied by the current B sample, then summed into the A sample. If enabled in
config30 writing to this register causes an auto-sync to be generated. This
loads the values of the QMC correction registers (config12, config13, and
config16) into the QMC block at the same time. When updating the QMC values
for the AB channel config16 should be written last. Programming config12 and
config13 will not affect the QMC settings.
Name
Function
Default
Value
All zeros
Table 29. Register Name: config17 – Address: 0x11, Default: 0x0000 (Causes Auto-Sync)
Register
Name
Address
Bit
config17
0x11
15
Reserved
Reserved for factory use.
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
0
12
Reserved
Reserved for factory use.
qmc_phaseCD(11:0)
QMC correction phase for the CD data path. The 12-bit qmc_phaseCD(11:0) word
is formatted as 2s complement and scaled to occupy a range of –0.5 to 0.49975
and a default phase correction of 0.00. To accomplish QMC phase correction, this
value is multiplied by the current D sample, then summed into the C sample. If
enabled in config30 writing to this register causes an auto-sync to be
generated. This loads the values of the CD-channel QMC block registers
(config14, config15, and config17) into the QMC block at the same time. When
updating the QMC values for the CD-channel config17 should be written last.
Programming config14 and config15 will not affect the QMC settings.
11:0
Name
Function
Default
Value
0
All zeros
Table 30. Register Name: config18 – Address: 0x12, Default: 0x0000 (Causes Auto-Sync)
Register
Name
Address
Bit
Name
Function
config18
0x12
15:0
phase_offsetAB(15:0)
Phase offset added to the AB data path NCO accumulator before the generation of
the SIN and COS values. The phase offset is added to the upper 16 bits of the NCO
accumulator results and these 16 bits are used in the sin/cos lookup tables. If
enabled in config31 writing to this register causes an auto-sync to be
generated. This loads the values of the fine mixer block registers (config18,
config20, and config21) at the same time. When updating the mixer values the
config18 should be written last. Programming config20 and config21 will not
affect the mixer settings.
Default
Value
0x0000
Table 31. Register Name: config19 – Address: 0x13, Default: 0x0000 (Causes Auto-Sync)
Register
Name
Address
Bit
config19
0x13
15:0
74
Name
phase_ offsetCD(15:0)
Function
Phase offset added to the CD data path NCO accumulator before the generation of
the SIN and COS values. The phase offset is added to the upper 16 bits of the NCO
accumulator results and these 16 bits are used in the sin/cos lookup tables. If
enabled in config31 writing to this register causes an auto-sync to be
generated. This loads the values of the CD-channel fine mixer block registers
(config19, config22 and config23) at the same time. When updating the mixer
values for the CD-channel config19 should be written last. Programming
config22 and config23 will not affect the mixer settings.
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Default
Value
0x0000
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Table 32. Register Name: config20 – Address: 0x14, Default: 0x0000
Register
Name
Address
Bit
config20
0x14
15:0
Name
phase_ addAB(15:0)
Default
Value
Function
The phase_addAB(15:0) value is used to determine the NCO frequency. The 2s
complement formatted value can be positive or negative. Each LSB represents
Fs/(2^32) frequency step.
0x0000
Table 33. Register Name: config21 – Address: 0x15, Default: 0x0000
Register
Name
Address
Bit
config21
0x15
15:0
Name
phase_ addAB(31:16)
Default
Value
Function
See config20 above.
0x0000
Table 34. Register Name: config22 – Address: 0x16, Default: 0x0000
Register
Name
Address
Bit
config22
0x16
15:0
Name
phase_ addCD(15:0)
Default
Value
Function
The phase_addCD(15:0) value is used to determine the NCO frequency. The 2s
complement formatted value can be positive or negative. Each LSB represents
Fs/(2^32) frequency step.
0x0000
Table 35. Register Name: config23 – Address: 0x17, Default: 0x0000
Register
Name
Address
Bit
config23
0x17
15:0
Name
phase_ addCD(31:16)
Default
Value
Function
See config22 above.
0x0000
Table 36. Register Name: config24 – Address: 0x18, Default: NA
Register
Name
Address
Bit
config24
0x18
15:13
Reserved
Reserved for factory use.
12
pll_reset
When set, the PLL loop filter (LPF) is pulled down to 0 V. Toggle from 1b to 0b to
restart the PLL if an over-speed lock-up occurs. Over-speed can happen when the
process is fast, the supplies are higher than nominal, etc. resulting in the feedback
dividers missing a clock.
0
11
pll_ndivsync_ena
When set, the LVDS SYNC input is used to sync the PLL N dividers.
1
10
pll_ena
When set, the PLL is enabled. When cleared, the PLL is bypassed.
0
9:8
Reserved
Reserved for factory use.
00
7:6
pll_cp(1:0)
PLL pump charge select
MM 00: No charge pump
MM 01: Single pump charge
MM 10: Not used
MM 11: Dual pump charge
00
5:3
pll_p(2:0)
PLL pre-scaler dividing module control.
MM 010: 2
MM 011: 3
MM 100: 4
MM 101: 5
MM 110: 6
MM 111: 7
MM 000: 8
001
2:0
pll_lfvolt(2:0)
PLL loop filter voltage. This three bit read-only indicator has step size of 0.4125 V.
The entire range covers from 0 V to 3.3 V. The optimal lock range of the PLL will be
from 010 to 101 (0.825 V to 2.063 V). Adjust pll_vco(5:0) for optimal lock range.
NA
Name
Default
Value
Function
001
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Table 37. Register Name: config25 – Address: 0x19, Default: 0x0440
Register
Name
Address
Bit
config25
0x19
15:8
pll_m(7:0)
M portion of the M/N divider of the PLL. If pll_m<7> = 0, the M divider value has
the range of pll_m<6:0>, spanning from 4 to 127. (0, 1, 2, and 3 are not valid.)
If pll_m<7> = 1, the M divider value has the range of 2 × pll_m<6:0>, spanning
from 8 to 254. (0, 2, 4, and 6 are not valid. M divider has even values only.)
0x04
7:4
pll_n(3:0)
N portion of the M/N divider of the PLL.
MM 0000: 1
MM 0001: 2
MM 0010: 3
MM 0011: 4
MM 0100: 5
MM 0101: 6
MM 0110: 7
MM 0111: 8
MM 1000: 9
MM 1001: 10
MM 1010: 11
MM 1011: 12
MM 1100: 13
MM 1101: 14
MM 1110: 15
MM 1111: 16
0100
3:2
pll_vcoitune(1:0)
PLL VCO bias tuning bits. Set to 01b for normal PLL operation.
00
1:0
Reserved
Reserved for factory use.
00
Name
Function
Default
Value
Table 38. Register Name: config26 – Address: 0x1A, Default: 0x0020
Register
Name
Address
Bit
config26
0x1A
15:10
76
Name
Function
Default
Value
pll_vco(5:0)
VCO frequency coarse tuning bits.
9
Reserved
Reserved for factory use.
0
8
Reserved
Reserved for factory use.
0
7
bias_sleep
When set, the bias amplifier is put into sleep mode.
0
6
tsense_sleep
Turns off the temperature sensor when asserted.
0
5
pll_sleep
When set, the PLL is put into sleep mode.
1
4
clkrecv_sleep
When asserted the clock input receiver gets put into sleep mode. This affects the
OSTR receiver as well.
0
3
sleepA
When set, the DACA is put into sleep mode.
0
2
sleepB
When set, the DACB is put into sleep mode.
0
1
sleepC
When set, the DACC is put into sleep mode.
0
0
sleepD
When set, the DACD is put into sleep mode.
0
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Table 39. Register Name: config27 – Address: 0x1B, Default: 0x0000
Register
Name
Address
Bit
config27
0x1B
15
extref_ena
Allows the device to use an external reference or the internal reference.
MM 0: Internal reference
MM 1: External reference
0
14
Reserved
Reserved for factory use.
0
13
Reserved
Reserved for factory use.
0
12
Reserved
Reserved for factory use.
0
11
fuse_sleep
Put the fuses to sleep when set high.
If SLEEP pin is set to logic HIGH before and during device power-up and
initialization, the fuse_sleep bit in register 0x1B, bit 11 must be written after
register 0x23 during device initialization register setup.
Note: Default value is ‘0’. Must be set to ‘1’ for proper operation
0
10
Reserved
Reserved for factory use.
0
9
Reserved
Reserved for factory use.
0
8
Reserved
Reserved for factory use.
0
7
Reserved
Reserved for factory use.
0
6
Reserved
Reserved for factory use.
atest
ATEST mode allows the user to check for the internal die voltages to ensure the
supply voltages are within the range. When ATEST mode is programmed, the
internal die voltages can be measured at the TXENABLE pin. The TXENABLE pin
(A32) must be floating without any pull-up or pull-down resistors.
In ATEST mode, the TXENABLE and sif_txenable logics are bypassed, and
output will be active at all time.
5:0
Name
Default
Value
Function
Config27, bit<5:0>
0
Description
000000
Expected Nominal
Voltage
001110
DACA AVSS
0V
001111
DACA DVDD
1.2 V
010000
DACA AVDD
3.3 V
010110
DACB AVSS
0V
010111
DACB DVDD
1.2 V
011000
DACB AVDD
3.3 V
011110
DACC AVSS
0V
011111
DACC DVDD
1.2 V
100000
DACC AVDD
3.3 V
100110
DACD AVSS
0V
100111
DACD DVDD
1.2 V
101000
DACD AVDD
3.3 V
110000
DIGVDD
1.2 V
000101
CLKVDD
1.2 V
Table 40. Register Name: config28 – Address: 0x1C, Default: 0x0000
Register
Name
Address
Bit
config28
0x1C
15:8
Reserved
Reserved for factory use.
0x00
7:0
Reserved
Reserved for factory use.
0x00
Name
Default
Value
Function
Table 41. Register Name: config29 – Address: 0x1D, Default: 0x0000
Register
Name
Address
Bit
config29
0x1D
15:8
Reserved
Reserved for factory use.
0x00
7:0
Reserved
Reserved for factory use.
0x00
Name
Function
Default
Value
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Table 42. Register Name: config30 – Address: 0x1E, Default: 0x1111
Register
Name
Address
Bit
config30
0x1E
15:12
syncsel_qmoffsetAB(3:0)
Selects the syncing source(s) of the AB data path double buffered QMC offset
registers. A 1b in the bit enables the signal as a sync source. More than one
sync source is permitted.
MM Bit 15: sif_sync (via config31)
MM Bit 14: SYNC
MM Bit 13: OSTR
MM Bit 12: Auto-sync from register write
0001
11:8
syncsel_ qmoffsetCD(3:0)
Selects the syncing source(s) of the CD data path double buffered QMC offset
registers. A 1b in the bit enables the signal as a sync source. More than one
sync source is permitted.
MM Bit 11: sif_sync (via config31)
MM Bit 10: SYNC
MM Bit 9: OSTR
MM Bit 8: Auto-sync from register write
0001
7:4
syncsel_ qmccorrAB(3:0)
Selects the syncing source(s) of the AB data path double buffered QMC
correction registers. A ‘1’ in the bit enables the signal as a sync source. More
than one sync source is permitted.
MM Bit 7: sif_sync (via config31)
MM Bit 6: SYNC
MM Bit 5: OSTR
MM Bit 4: Auto-sync from register write
0001
3:0
syncsel_ qmccorrCD(3:0)
Selects the syncing source(s) of the CD data path double buffered QMC
correction registers. A 1b in the bit enables the signal as a sync source. More
than one sync source is permitted.
MM Bit 3: sif_sync (via config31)
MM Bit 2: SYNC
MM Bit 1: OSTR
MM Bit 0: Auto-sync from register write
0001
Name
Function
Default
Value
Table 43. Register Name: config31 – Address: 0x1F, Default: 0x1140
Register
Name
Address
Bit
config31
0x1F
15:12
syncsel_mixerAB(3:0)
Selects the syncing source(s) of the AB data path double buffered mixer
registers. A 1b in the bit enables the signal as a sync source. More than one
sync source is permitted.
MM Bit 15: sif_sync (via config31)
MM Bit 14: SYNC
MM Bit 13: OSTR
MM Bit 12: Auto-sync from register write
0001
11:8
syncsel_ mixerCD(3:0)
Selects the syncing source(s) of the CD data path double buffered mixer
registers. A 1b in the bit enables the signal as a sync source. More than one
sync source is permitted.
MM Bit 11: sif_sync (via config31)
MM Bit 10: SYNC
MM Bit 9: OSTR
MM Bit 8: Auto-sync from register write
0001
7:4
syncsel_nco(3:0)
Selects the syncing source(s) of the two NCO accumulators. A 1b in the bit
enables the signal as a sync source. More than one sync source is permitted.
MM Bit 7: sif_sync (via config31)
MM Bit 6: SYNC
MM Bit 5: OSTR
MM Bit 4: FRAME
0100
3:2
syncsel_dataformatter(1:
0)
Selects the syncing source of the data formatter. Unlike the other syncs only
one sync source is allowed.
MM 00: FRAME
MM 01: SYNC
MM 10: No sync
MM 11: No sync
00
1
sif_sync
SIF created sync signal. Set to 1b to cause a sync and then clear to 0b to
remove it.
0
0
Reserved
Reserved for factory use.
0
78
Name
Function
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Default
Value
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Table 44. Register Name: config32 – Address: 0x20, Default: 0x2400
Register
Name
Address
Bit
config32
0x20
15:12
syncsel_fifoin(3:0)
Selects the syncing source(s) of the FIFO input side. A ‘1’ in the bit enables the
signal as a sync source. More than one sync source is permitted.
MM Bit 15: sif_sync (via config31)
MM Bit 14: Always zero
MM Bit 13: FRAME
MM Bit 12: SYNC
0010
11:8
syncsel_fifoout(3:0)
Selects the syncing source(s) of the FIFO output side. A 1b in the bit enables the
signal as a sync source. More than one sync source is permitted.
MM Bit 11: sif_sync (via config31)
MM Bit 10: OSTR – Dual Sync Sources Mode
MM Bit 9: FRAME – Single Sync Source mode
MM Bit 8: SYNC – Single Sync Source mode
0100
7:1
Reserved
Reserved for factory use.
0000
clkdiv_sync_sel
Selects the signal source for clock divider synchronization.
0
Name
Default
Value
Function
clkdiv_sync_sel
0
Sync Source
0
OSTR
1
FRAME or SYNC, based on syncsel_fifoin source
selection (config32, bit<15:12>)
Table 45. Register Name: config33 – Address: 0x21, Default: 0x0000
Register
Name
Address
Bit
config33
0x21
15:0
Name
Reserved
Default
Value
Function
Reserved for factory use.
0x0000
Table 46. Register Name: config34 – Address: 0x22, Default: 0x1B1B
Register
Name
Address
Bit
config34
0x22
15:14
pathA_in_sel(1:0)
Selects the word used for the A channel path.
00
13:12
pathB_in_sel(1:0)
Selects the word used for the B channel path.
01
11:10
pathC_in_sel(1:0)
Selects the word used for the C channel path.
10
9:8
pathD_in_sel(1:0)
Selects the word used for the D channel path.
11
7:6
DACA_out_sel(1:0)
Selects the word used for the DACA output.
00
5:4
DACB_out_sel(1:0)
Selects the word used for the DACB output.
01
3:2
DACC_out_sel(1:0)
Selects the word used for the DACC output.
10
1:0
DACD_out_sel(1:0)
Selects the word used for the DACD output.
11
Name
Function
Default
Value
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Table 47. Register Name: config35 – Address: 0x23, Default: 0xFFFF
Register
Name
Address
Bit
config35
0x23
15:0
Name
sleep_cntl(15:0)
Default
Value
Function
Controls the routing of the CMOS SLEEP signal (pin B40 for the DAC3484IRKD and
pin B8 for the DAC3484IZAY) to different blocks. When a bit in this register is set, the
SLEEP signal will be sent to the corresponding block. The block will only be disabled
when the SLEEP is logic HIGH and the correspond bit is set to 1b.
0xFFFF
These bits do not override SIF bits in config26 that control the same sleep function.
sleep_cntl(bit)
Function
15
DACA sleep
14
DACB sleep
13
DACC sleep
12
DACD sleep
11
Clock receiver sleep
10
PLL sleep
9
LVDS data sleep
8
LVDS control sleep
7
Temp sensor sleep
6
reserved
5
Bias amplifier sleep
All others
not used
Table 48. Register Name: config36 – Address: 0x24, Default: 0x0000
Register
Name
Address
Bit
config36
0x24
15:13
datadly(2:0)
Controls the delay of the data inputs through the LVDS receivers. Each LSB adds
approximately 50 ps. Refer to Digital Input Timing Specifications Table for details.
MM 0: Minimum
000
12:10
clkdly(2:0)
Controls the delay of the data clock through the LVDS receivers. Each LSB adds
approximately 50 ps. Refer to Digital Input Timing Specifications Table for details.
MM 0: Minimum
000
9:0
Reserved
Reserved for factory use.
Name
Function
Default
Value
0x000
Table 49. Register Name: config37 – Address: 0x25, Default: 0x7A7A
Register
Name
Address
Bit
config37
0x25
15:0
Name
iotest_pattern0
Function
Dataword0 in the IO test pattern. It is used with the seven other words to test the input data.
At the start of the IO test pattern, this word should be aligned with rising edge of FRAME or
SYNC signal to indicate sample 0.
Default
Value
0x7A7A
Table 50. Register Name: config38 – Address: 0x26, Default: 0xB6B6
Register
Name
Address
Bit
config38
0x26
15:0
Name
iotest_pattern1
Function
Dataword1 in the IO test pattern. It is used with the seven other words to test the input data.
Default
Value
0xB6B6
Table 51. Register Name: config39 – Address: 0x27, Default: 0xEAEA
Register
Name
Address
Bit
config39
0x27
15:0
Name
iotest_pattern2
Function
Dataword2 in the IO test pattern. It is used with the seven other words to test the input
data.
Default
Value
0xEAEA
Table 52. Register Name: config40 – Address: 0x28, Default: 0x4545
Register
Name
Address
Bit
config40
0x28
15:0
80
Name
iotest_pattern3
Function
Default
Value
Dataword3 in the IO test pattern. It is used with the seven other words to test the input data.
0x4545
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Table 53. Register Name: config41 – Address: 0x29, Default: 0x1A1A
Register
Name
Address
Bit
Name
config41
0x29
15:0
iotest_pattern4
Default
Value
Function
Dataword4 in the IO test pattern. It is used with the seven other words to test the input data.
0x1A1A
Table 54. Register Name: config42 – Address: 0x2A, Default: 0x1616
Register
Name
Address
Bit
config42
0x2A
15:0
Name
iotest_pattern5
Default
Value
Function
Dataword5 in the IO test pattern. It is used with the seven other words to test the input
data.
0x1616
Table 55. Register Name: config43 – Address: 0x2B, Default: 0xAAAA
Register
Name
Address
Bit
config43
0x2B
15:0
Name
iotest_pattern6
Default
Value
Function
Dataword6 in the IO test pattern. It is used with the seven other words to test the input
data.
0xAAAA
Table 56. Register Name: config44 – Address: 0x2C, Default: 0xC6C6
Register
Name
Address
Bit
config44
0x2C
15:0
Name
iotest_pattern7
Default
Value
Function
Dataword7 in the IO test pattern. It is used with the seven other words to test the input
data.
0xC6C6
Table 57. Register Name: config45 – Address: 0x2D, Default: 0x0004
Register
Name
Address
Bit
config45
0x2D
15
reserved
Reserved for factory use
0
14
ostrtodig_sel
When set, the OSTR signal is passed directly to the digital block. This is the signal that
is used to clock the dividers.
0
Name
Default
Value
Function
13
ramp_ena
When set, a ramp signal is inserted in the input data at the FIFO input.
12:1
Reserved
Reserved for factory use.
0
sifdac_ena
When set, the DAC output is set to the value in sifdac(15:0) in register config48. In this
mode, sif_txena in config3 and TXENABLE inputs are ignored.
0
0000
0000
0010
0
Table 58. Register Name: config46 – Address: 0x2E, Default: 0x0000
Register
Name
Address
Bit
config46
0x2E
15:8
grp_delayA(7:0)
Sets the group delay function for DACA. The maximum delay ranges from 30 ps to 100
ps and is dependent on DAC sample clock. Contact TI for specific application
information.
0x00
7:0
grp_delayB(7:0)
Sets the group delay function for DACB. The maximum delay ranges from 30 ps to 100
ps and is dependent on DAC sample clock. Contact TI for specific application
information.
0x00
Name
Default
Value
Function
Table 59. Register Name: config47 – Address: 0x2F, Default: 0x0000
Register
Name
Address
Bit
config47
0x2F
15:8
grp_delayC(7:0)
Sets the group delay function for DACC. The maximum delay ranges from 30 ps to
100 ps and is dependent on DAC sample clock. Contact TI for specific application
information.
0x00
7:0
grp_delayD(7:0)
Sets the group delay function for DACD. The maximum delay ranges from 30 ps to
100 ps and is dependent on DAC sample clock. Contact TI for specific application
information.
0x00
Name
Default
Value
Function
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Table 60. Register Name: config48 – Address: 0x30, Default: 0x0000
Register
Name
Address
Bit
config48
0x30
15:0
Name
sifdac(15:0)
Function
Value sent to the DACs when sifdac_ena is asserted. DATACLK must be running to
latch this value into the DACs. The format would be based on twos in register config2.
Default
Value
0x0000
Table 61. Register Name: Version – Address: 0x7F, Default: 0x540C (Read Only)
Register
Name
Address
Bit
version
0x7F
15:10
Reserved
Reserved for factory use.
9
Reserved
Reserved for factory use.
0
8:7
Reserved
Reserved for factory use.
00
6:5
Reserved
Reserved for factory use.
00
4:3
deviceid(1:0)
Returns 01b for DAC3484.
01
2:0
versionid(2:0)
A hardwired register that contains the version of the chip.
100
82
Name
Function
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Default
Value
010101
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The DAC3484 is a quad 16-bit DAC with max input data rate of up to 312.5 MSPS per DAC and max DAC
update rate of 1.25 GSPS after the final, selectable interpolation stages. With build-in interpolation filter of 2x, 4x,
8x, and 16x options, the lower input data rate can be interpolated all the way to 1.25 GSPS. This allows the DAC
to update the samples at higher rate, and pushes the DAC images further away to relax anti-image filer
specification due to the increased Nyquist bandwidth. With integrated coarse and fine mixers, baseband signal
can be upconverted to an intermediate frequency (IF) signal between the baseband processor and post-DAC
analog signal chains.
The DAC can output baseband or IF when connected to post-DAC analog signals chain components such as
transformers or IF amplifiers. When used in conjunction with TI RF quadrature modulator such as the TRF3705,
the DAC and RF modulator can function as a set of baseband or IF upconverter. With integrated QMC circuits,
the LO offset and the sideband artifacts can be properly corrected in the direct up-conversion applications. The
DAC3484 provides the bandwidth, performance, small footprint, and lower power consumption needed for multimode 2G/3G/4G cellular base stations to migrate to more advanced technologies, such as LTE-Advanced and
carrier aggregation on multiple antennas.
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8.2 Typical Applications
8.2.1 IF Based LTE Transmitter
Figure 91 shows an example block diagram for a direct conversion radio. The design requires a single carrier,
20-MHz LTE signal. The system has digital-predication (DPD) to correct up to 5th order distortion so the total
DAC output bandwidth is 100 MHz. Interpolation is used to output the signal at highest sampling rate possible to
simplify the analog filter requirements and move high order harmonics out of band (due to wider Nyquist zone).
The internal PLL is used to generate the final DAC output clock from a reference clock of 491.52 MHz.
DAC3484
Complex Mixer
(48-bit NCO)
FPGA
16-bit DAC
TRF3705
RF
TRF3705
RF
16-bit DAC
xN
Complex Mixer
(48-bit NCO)
LVDS Interface
xN
xN
16-bit DAC
16-bit DAC
xN
Clock Distribution
PLL
TRF3765
DACCLK
SYSREF
LMK04828
Figure 91. Dual Low-IF Wideband LTE Transmitter Diagram
8.2.1.1 Design Requirements
For this design example, use the parameters listed in Table 62 as the input parameters.
Table 62. Design Parameters
DESIGN PARAMETER
84
EXAMPLE VALUE
Signal Bandwidth (BWsignal)
20 MHz
Total DAC Output Bandwidth (BWtotal)
100 MHz
DAC PLL
On
DAC PLL Reference Frequency
491.52 MHz
Maximum FPGA LVDS Rate
491.52 Mbps
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8.2.1.2 Detailed Design Procedure
8.2.1.2.1 Data Input Rate
Nyquist theory states that the data rate must be at least two times the highest signal frequency. The data will be
sent to the DAC as complex baseband data. Due to the quadrature nature of the signal, each in-phase (I
component) and quadrature (Q component) need to have 50 MHz of bandwidth to construct 100 MHz of complex
bandwidth. Since the interpolation filter design is not the ideal half-band filter design with infinite roll-off at
FDATA/2 (refer to FIR Filters section for more detail), the filter limits the useable input bandwidth to about 40
percent of FDATA. Therefore, the minimum data input rate is 125 MSPS. Since the standard telecom data rate is
typically multiples of 30.72 MSPS, the DAC input data rate is chosen to be eight times of 30.72 MSPS, which is
245.76 MSPS.
8.2.1.2.2 Interpolation
It is desired to use the highest DAC output rate as possible to move the DAC images further from the signal of
interest to ease analog filter requirement. The DAC output rate must be greater than two times the highest output
frequency of 200 MHz, which is greater than 400 MHz. Table 63 shows the possible DAC output rates based on
the data input rate and available interpolation settings. The DAC image frequency is also listed.
Table 63. Interpolation
FDATA
INTERPOLATION
FDAC
POSSIBLE?
LOWEST IMAGE
FREQUENCY
DISTANCE FROM BAND OF
INTEREST
245.76 MSPS
1
245.76 MSPS
No
N/A
N/A
245.76 MSPS
2
491.52 MSPS
Yes
318.64 MHz
145.76 MHz
245.76 MSPS
4
983.04 MSPS
Yes
810.16 MHz
637.28 MHz
245.76 MSPS
8
1966.08 MSPS
No
N/A
N/A
245.76 MSPS
16
3932.16 MSPS
No
N/A
N/A
8.2.1.2.3 LO Feedthrough and Sideband Correction
For typical IF based systems, the IF location is selected such that the image location and the LO feedthrough
location is far from the signal location. The minimum distance is based on the bandpass filter roll-off and
attenuation level at the LO feedthrough and image location. If sufficient attenuation level of these two artifacts
meets the system requirement, then further digital cancellation of these artifacts may not be needed.
Although the I/Q modulation process will inherently reduce the level of the RF sideband signal, an IF based
transmitter without sufficient RF image rejection capabilities or an zero-IF based system (detail in the next
section) will likely need additional sideband suppression to maximize performance. Further, any mixing process
will result in some feedthrough of the LO source. The DAC3484 has build-in digital features to cancel both the
LO feedthrough and sideband signal. The LO feedthrough is corrected by adding a DC offset to the DAC outputs
until the LO feedthrough power is suppressed. The sideband suppression can be improved by correcting the gain
and phase differences between the I and Q analog outputs through the digital QMC block. Besides gain and
phase differences between the I and Q analog outputs, group delay differences may also be present in the signal
path and are typically contributed by group delay variations of post DAC image reject analog filters and PCB
trace variations. Since delay in time translates to higher order linear phase variation, the sideband of a wideband
system may not be completely suppressed by typical digital QMC block. The DAC3484 has integrated group
delay correction feature to provide delay adjustments. (The maximum group delay correction ranges from 30 ps
to 100 ps and is dependent on DAC sample clock. Contact TI for specific application information.) Moreover,
system designer may implement additional linear group delay compensation in the host processor to the DAC to
perform higher order sideband suppression.
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8.2.1.3 Application Curves
The ACPR performance for LTE 20 MHz TM1.1 are shown in Figure 92, Figure 93, Figure 93, and Figure 93.
The figures provide comparisons between two major LTE bands such as 2.14 GHz and 2.655 GHz, and also
comparisons between two different DAC clocking options such as DAC on-chip PLL mode and external clocking
mode.
DAC Output IF = 122.88 MHz, LO = 2017.12 MHz, DAC Clock =
External Clock Source from LMK04806
Figure 92. 20MHz TM1.1 LTE Carrier at 2.14GHz
DAC Output IF = 122.88 MHz, LO = 2532.12 MHz, DAC Clock =
External Clock Source from LMK04806
Figure 94. 20MHz TM1.1 LTE Carrier at 2.655GHz
86
DAC Output IF = 122.88 MHz, LO = 2017.12 MHz, DAC Clock =
DAC3484 On-Chip PLL
Figure 93. 20MHz TM1.1 LTE Carrier at 2.14GHz
DAC Output IF = 122.88 MHz, LO = 2532.12 MHz, DAC Clock =
DAC3484 On-Chip PLL
Figure 95. 20MHz TM1.1 LTE Carrier at 2.655GHz
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8.2.2 Direct Upconversion (Zero IF) LTE Transmitter
Figure 91 shows an example block diagram for a direct conversion radio. The design specification requires that
the desired output bandwidth is 40 MHz, which could be, for instance, a typical LTE signal. The system has DPD
to correct up to 5th order distortion so the total DAC output bandwidth is 200 MHz. Interpolation is used to output
the signal at the highest sampling rate possible to simplify the analog filtering requirements and move high order
harmonics out of band (due to wider Nyquist zone). The DAC sampling clock is provided by high quality clock
synthesizer such as the LMK0480x family.
DAC3484
QMC Gain, Phase, Offset
FPGA
xN
QMC Gain, Phase, Offset
LVDS Interface
xN
xN
xN
16-bit DAC
TRF3705
RF
TRF3705
RF
16-bit DAC
16-bit DAC
16-bit DAC
Clock Distribution
TRF3765
DACCLK
SYSREF
LMK04828
Figure 96. Zero LTE Transmitter Diagram
8.2.2.1 Design Requirements
For this design example, use the parameters listed in Table 64 as the input parameters.
Table 64. Design Parameters
DESIGN PARAMETER
EXAMPLE VALUE
Signal Bandwidth (BWsignal)
40 MHz
Total DAC Output Bandwidth (BWtotal)
200 MHz
DAC PLL
Off
Maximum FPGA LVDS Rate
1228.8 Mbps
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8.2.2.2 Detailed Design Procedure
8.2.2.2.1 Data Input Rate
Nyquist theory states that the data rate must be at least two times the highest signal frequency. The data will be
sent to the DAC as complex baseband data. Due to the quadrature nature of the signal, each in-phase (I
component) and quadrature (Q component) need to have 100 MHz of bandwidth to construct 200 MHz of
complex bandwidth. Since the interpolation filter design is not the ideal half-band filter design with infinite roll-off
at FDATA/2 (refer to FIR Filters section for more detail), the filter limits the useable input bandwidth to about 44
percent of FDATA with less than 0.1dB of FIR filter roll-off. Therefore, the minimum data input rate is 228 MSPS.
Since the standard telecom data rate is typically multiples of 30.72 MSPS, the DAC input data rate is chosen to
be 10 times of 30.72 MSPS, which is 307.2 MSPS.
8.2.2.2.2 Interpolation
It is desired to use the highest DAC output rate as possible to move the DAC images further from the signal of
interest to ease analog filter requirement. The DAC output rate must be greater than two times the highest output
frequency of 100 MHz, which is greater than 200 MHz. The table below shows the possible DAC output rates
based on the data input rate and available interpolation settings. The DAC image frequency is also listed.
Table 65. Interpolation
FDATA
INTERPOLATION
FDAC
POSSIBLE?
LOWEST IMAGE
FREQUENCY
DISTANCE FROM BAND OF
INTEREST
307.2 MSPS
1
307.2 MSPS
Yes
287.2 MHz
267.2 MHz
307.2 MSPS
2
614.4 MSPS
Yes
594.4 MHz
574.4 MHz
307.2 MSPS
4
1228.8 MSPS
Yes
1208.8
1188.8
307.2 MSPS
8
2457.6 MSPS
No
N/A
N/A
307.2 MSPS
16
4915.2 MSPS
No
N/A
N/A
8.2.2.2.3 LO Feedthrough and Sideband Correction
Refer to LO Feedthrough and Sideband Correction section of IF based LTE Transmitter design.
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8.2.2.3 Application Curves
The ACPR performance for LTE 20MHz TM1.1 are shown in Figure 97 and Figure 98. The figures provide
comparisons between two major LTE bands such as 2.14 GHz and 2.655 GHz with DAC clocking option set to
external clocking mode.
DAC Output IF = 0 MHz, LO = 2140 MHz, DAC Clock = External
Clock Source from LMK04806
Figure 97. 4x10MHz TM1.1 LTE Carrier at 2.14GHz
DAC Output IF = 0 MHz, LO = 2655 MHz, DAC Clock = External
Clock Source from LMK04806
Figure 98. 4x10MHz TM1.1 LTE Carrier at 2.655GHz
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9 Power Supply Recommendations
Powered by CLKVDD
IOUTP
Sample Clock
Switch
Drivers
Decoder
Logic
=
Digital Input Data
DAC
IOUTN
Analog Output
As shown in Figure 99, the DAC3484 device has various power rails and has two primary voltages of 1.2 V and
3.3 V. Some of the DAC power rails such as CLKVDD and AVDD are more noise sensitive than other rails
because they are mainly powering the switch drivers for the current switch array and the current bias circuits,
respectively. These circuits are the main analog DAC core. Any power supply noises such as switching power
supply ripple may be modulated directly onto the signal of interest. These two power rails should be powered by
low noise power supplies such as LDO. Powering the rail directly with switching power supplies is not
recommended for these two rails.
Switch
Array
Powered by DACVDD
Powered by
AVDD
Bias
Circuit
Current
Source Array
Figure 99. Interpolation Filters, NCOs, and QMC Blocks Powered by DIGVDD
With the DAC3484 being a mixed signal device, the device contains circuits that bridges the digital section and
the analog section. The DACVDD powers these sections. System designer can design this rail in secondary
priority. Powering the rail with LDO is recommended. Unless system designer pays special care to supply filtering
and power supply routing/placement, powering the rail directly with switching power supplies is not
recommended for this rail.
Since digital circuits have more inherent noise immunity than analog circuits, the power supply noise
requirements for DIGVDD of the digital section of the device may be relaxed and placed at a lower priority.
Depending on the spur level requirement, routing and placement of the power supply, power the rail directly with
switching power supplies can be possible. With the digital logics running, the DIGVDD rail may draw significant
current. If the power supply traces and filtering network have significant DC resistance loss (for example, DCR),
then the final supply voltage seen by the DIGVDD rail may not be sufficient to meet the minimum power supply
level. For instance, with 450 mA of DIGVDD current and about 0.1 Ω of DCR from the ferrite bead, the final
supply voltage at the DIGVDD pins may be 1.2 V – 0.045 V = 1.155 V. This is fairly close to the minimum supply
voltage range of 1.14 V. System designer may need to elevate the power supply voltage according to the DCR
level or design a feedback network for the power supply to account for associated voltage drop. To ensure power
supply accuracy and to account for power supply filter network loss at operating conditions, the use of the
ATEST function in register config27 to check the internal power supply nodes is recommended.
The table below is a summary of the various power supply nodes of the DAC. Care should be taken to keep
clean power supplies routing away from noisy digital supplies. It is recommended to use at least two power
layers. Power supplies for digital circuits tend to have more switching activities and are typically noisier, and
system designer should avoid sharing the digital power rail (for example, power supplies for FPGA or DIGVDD of
DAC3484) with the analog power rail (for example, CLKVDD and AVDD of DAC3484). Avoid placing noisy
supplies and clean supplies on adjacent board layers and use a ground layer between these two supplies if
possible. All supply pins should be decoupled as close to the pins as possible by using small value capacitors,
with larger bulk capacitors placed further away and near the power supply source.
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Table 66. Power Rails
POWER
RAILS
TYPICAL
VOLTAGE
NOISE
SENSITIVITY
RECOMMENDATIONS
POWER
SUPPLY
DESIGN
PRIORITY
CLKVDD
1.2 V
High
Provide clean supply to the rail. Avoid spurious noise or
coupling from other supplies
High
AVDD
3.3 V
High
Provide clean supply to the rail. Avoid spurious noise or
coupling from other supplies
High
DACVDD
1.2 V
Medium
Provide clean supply to the rail. Avoid spurious noise or
coupling from other supplies
Medium
DIGVDD
1.2 V
Low
Keep Away from other noise sensitive nodes in
placement and routing.
Low
10 Layout
10.1 Layout Guidelines
The design of the PCB is critical to achieve the full performance of the DAC3484 device. Defining the PCB
stackup should be the first step in the board design. Experience has shown that at least six layers are required to
adequately route all required signals to and from the device. Each signal routing layer must have an adjacent
solid ground plane to control signal return paths to have minimal loop areas and to achieve controlled
impedances for microstrip and stripline routing. Power planes must also have adjacent solid ground planes to
control supply return paths. Minimizing the space between supply and ground planes improves performance by
increasing the distributed decoupling.
Although the DAC3484 device consists of both analog and digital circuitry, TI highly recommends solid ground
planes that encompass the device and its input and output signal paths. TI does not recommend split ground
planes that divide the analog and digital portions of the device. Split ground planes may improve performance if a
nearby, noisy, digital device is corrupting the ground reference of the analog signal path. When split ground
planes are employed, one must carefully control the supply return paths and keep the paths on top of their
respective ground reference planes.
Quality analog output signals and input conversion clock signal path layout is required for full dynamic
performance. Symmetry of the differential signal paths and discrete components in the path is mandatory, and
symmetrical shunt-oriented components should have a common grounding via. The high frequency requirements
of the analog output and clock signal paths necessitate using differential routing with controlled impedances and
minimizing signal path stubs (including vias) when possible.
Coupling onto or between the clock and output signals paths should be avoided using any isolation techniques
available including distance isolation, orientation planning to prevent field coupling of components like inductors
and transformers, and providing well coupled reference planes. Via stitching around the clock signal path and the
input analog signal path provides a quiet ground reference for the critical signal paths and reduces noise
coupling onto these paths. Sensitive signal traces must not cross other signal traces or power routing on
adjacent PCB layers, rather a ground plane must separate the traces. If necessary, the traces should cross at
90° angles to minimize crosstalk.
The substrate (dielectric) material requirements of the PCB are largely influenced by the speed and length of the
high speed serial lanes. Affordable and common FR4 varieties are adequate in most cases.
Coupling of ambient signals into the signal path is reduced by providing quiet, close reference planes and by
maintaining signal path symmetry to ensure the coupled noise is common-mode. Faraday caging may be used in
very noise environment and high dynamic range applications to isolate the signal path.
The following layout guidelines correspond to the layout shown in Figure 100.
1. DAC output termination resistors should be placed as close to the output pins as possible to provide a DC
path to ground and set the source impedance matching.
2. For DAC on-chip PLL clocking mode, if the external loop filter is not used, leave the loop filter pin floating
without any board routing nearby. Signals coupling to this node may cause clock mixing spurs in the DAC
output.
3. Route the high speed LVDS lanes as impedance-controlled, tightly-coupled, differential traces.
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Layout Guidelines (continued)
4. Maintain a solid ground plane under the LVDS lanes without any ground plane splits.
5. Simulation of the LVDS channel with DAC3484 IBIS model is recommended to verify good eye opening of
the data patterns.
6. Keep the OSTR signal routing away from the DACCLK routing to reduce coupling.
7. Keep routing for RBIAS short, for instance a resistor can be placed on the board directly connecting the
RBIAS pin to the ground layer.
The following layout guidelines correspond to the layouts shown in Figure 101 and Figure 102.
1. Noise power supplies should be routed away from clean supplies. Use two power plane layers, preferably
with a ground layer in between.
2. As shown in Figure 101 and Figure 102, both layers three and four are designated for power supply planes.
The DAC analog powers are all in the same layer to avoid coupling with each other, and the planes are
copied from layer three to layer four for double the copper coverage area.
3. Decoupling capacitors should be placed as close to the supply pins as possible. For instance, a capacitor
can be placed on the bottom of the board directly connecting the supply pin to a ground layer.
10.1.1 Assembly
Information regarding the package and assembly of the WQFN-MR package version of the DAC3484 can be
found at the end of the data sheet and also on the following application note: SZZA059
Information regarding the package and assembly of the ZAY package version of the DAC3484 can be found at
the end of the data sheet and also on the following application note: SPRAA99
10.2 Layout Examples
6
2
3
4
1
5
7
Figure 100. Top Layer of DAC3484 Layout Showing High Speed Signals such as LVDS Bus, DACCLK,
OSTR, and DAC Outputs. Layout Example from TSW3085EVM Rev D
92
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Layout Examples (continued)
PLLVDD
CLKVDD
DACVDD
AVDD
DIGVDD
Figure 101. Third Layer of DAC3484 Layout Showing Power Layers. Layout Example from DAC3484EVM
Rev H
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Layout Examples (continued)
PLLVDD
CLKVDD
DVDD
DACVDD
AVDD
Figure 102. Fourth Layer of DAC3484 Layout Showing Power Layers. Layout Example from
DAC3484EVM Rev H
94
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11 Device and Documentation Support
11.1 Device Support
11.1.1 Third-Party Products Disclaimer
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.
11.1.2 Device Nomenclature
11.1.2.1 Definition of Specifications
Adjacent Carrier Leakage Ratio (ACLR): Defined for a 3.84Mcps 3GPP W-CDMA input signal measured in a
3.84-MHz bandwidth at a 5-MHz offset from the carrier with a 12dB peak-to-average ratio.
Analog and Digital Power Supply Rejection Ratio (APSSR, DPSSR): Defined as the percentage error in the
ratio of the delta IOUT and delta supply voltage normalized with respect to the ideal IOUT current.
Differential Nonlinearity (DNL): Defined as the variation in analog output associated with an ideal 1 LSB
change in the digital input code.
Gain Drift: Defined as the maximum change in gain, in terms of ppm of full-scale range (FSR) per °C, from the
value at ambient (25°C) to values over the full operating temperature range.
Gain Error: Defined as the percentage error (in FSR%) for the ratio between the measured full-scale output
current and the ideal full-scale output current.
Integral Nonlinearity (INL): Defined as the maximum deviation of the actual analog output from the ideal output,
determined by a straight line drawn from zero scale to full scale.
Intermodulation Distortion (IMD3): The two-tone IMD3 is defined as the ratio (in dBc) of the 3rd-order
intermodulation distortion product to either fundamental output tone.
Offset Drift: Defined as the maximum change in DC offset, in terms of ppm of full-scale range (FSR) per °C,
from the value at ambient (25°C) to values over the full operating temperature range.
Offset Error: Defined as the percentage error (in FSR%) for the ratio between the measured mid-scale output
current and the ideal mid-scale output current.
Output Compliance Range: Defined as the minimum and maximum allowable voltage at the output of the
current-output DAC. Exceeding this limit may result reduced reliability of the device or adversely affecting
distortion performance.
Reference Voltage Drift: Defined as the maximum change of the reference voltage in ppm per degree Celsius
from value at ambient (25°C) to values over the full operating temperature range.
Spurious Free Dynamic Range (SFDR): Defined as the difference (in dBc) between the peak amplitude of the
output signal and the peak spurious signal within the first Nyquist zone.
Noise Spectral Density (NSD): Defined as the difference of power (in dBc) between the output tone signal
power and the noise floor of 1-Hz bandwidth within the first Nyquist zone.
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11.2 Documentation Support
11.2.1 Related Documentation
• Design Summary Multi-row Quad Flat No-lead (MRQFN) Application Report (SZZA059)
• nFBGA Packaging Application Report (SPRAA99)
• DAC348x Device Configuration and Synchronization Application Report (SLAA584)
• Semiconductor and IC Package Thermal Metrics Application Report (SPRA953)
• Using DAC348x with Fault Detection and Auto Output Shut-off Feature Application Report (SLAA585)
11.3 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.4 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.5 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
11.6 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
96
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PACKAGE OPTION ADDENDUM
www.ti.com
29-Oct-2015
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
DAC3484IRKD25
ACTIVE
WQFN-MR
RKD
88
25
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-3-260C-168 HR
-40 to 85
DAC3484I
DAC3484IRKDR
ACTIVE
WQFN-MR
RKD
88
2000
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-3-260C-168 HR
-40 to 85
DAC3484I
DAC3484IRKDT
ACTIVE
WQFN-MR
RKD
88
250
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-3-260C-168 HR
-40 to 85
DAC3484I
DAC3484IZAY
ACTIVE
NFBGA
ZAY
196
160
Green (RoHS
& no Sb/Br)
SNAGCU
Level-3-260C-168 HR
-40 to 85
DAC3484I
DAC3484IZAYR
ACTIVE
NFBGA
ZAY
196
1000
Green (RoHS
& no Sb/Br)
SNAGCU
Level-3-260C-168 HR
-40 to 85
DAC3484I
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
29-Oct-2015
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
29-Oct-2015
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
DAC3484IRKDR
WQFNMR
RKD
88
2000
330.0
16.4
9.3
9.3
1.5
12.0
16.0
Q2
DAC3484IRKDT
WQFNMR
RKD
88
250
330.0
16.4
9.3
9.3
1.5
12.0
16.0
Q2
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
29-Oct-2015
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
DAC3484IRKDR
WQFN-MR
RKD
88
2000
336.6
336.6
28.6
DAC3484IRKDT
WQFN-MR
RKD
88
250
336.6
336.6
28.6
Pack Materials-Page 2
PACKAGE OUTLINE
ZAY0196A
NFBGA - 1.4 mm max height
SCALE 1.100
PLASTIC BALL GRID ARRAY
12.1
11.9
A
B
BALL A1 CORNER
12.1
11.9
1.4 MAX
C
SEATING PLANE
BALL TYP
0.45
TYP
0.35
0.12 C
10.4 TYP
(0.8) TYP
SYMM
P
N
(0.8) TYP
M
L
K
10.4
TYP
J
SYMM
H
G
F
E
196X
D
C
B
0.55
0.45
0.15
0.05
C A
C
B
A
0.8 TYP
BALL A1 CORNER
1
2
3
4
5
6
7
8
9 10 11 12 13 14
0.8 TYP
4219823/A 09/2015
NOTES:
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
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EXAMPLE BOARD LAYOUT
ZAY0196A
NFBGA - 1.4 mm max height
PLASTIC BALL GRID ARRAY
(0.8) TYP
196X ( 0.4)
1
2
4
3
5
6
7
8
9
10
11
12
13
14
A
B
(0.8) TYP
C
D
E
F
G
SYMM
H
J
K
L
M
N
P
SYMM
LAND PATTERN EXAMPLE
SCALE:8X
0.05 MAX
( 0.4)
METAL
METAL UNDER
SOLDER MASK
0.05 MIN
SOLDER MASK
OPENING
SOLDER MASK
DEFINED
NON-SOLDER MASK
DEFINED
(PREFERRED)
( 0.4)
SOLDER MASK
OPENING
SOLDER MASK DETAILS
NOT TO SCALE
4219823/A 09/2015
NOTES: (continued)
3. Final dimensions may vary due to manufacturing tolerance considerations and also routing constraints.
For information, see Texas Instruments literature number SPRAA99 (www.ti.com/lit/spraa99).
www.ti.com
EXAMPLE STENCIL DESIGN
ZAY0196A
NFBGA - 1.4 mm max height
PLASTIC BALL GRID ARRAY
( 0.4) TYP
(0.8) TYP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
(0.8) TYP
B
C
D
E
F
G
SYMM
H
J
K
L
M
N
P
SYMM
SOLDER PASTE EXAMPLE
BASED ON 0.15 mm THICK STENCIL
SCALE:8X
4219823/A 09/2015
NOTES: (continued)
4. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release.
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