TI1 DAC3482 Dual-channel, 16-bit, 1.25 gsps digital-to-analog converter (dac) Datasheet

DAC3482
SLAS748A – MARCH 2011 – REVISED JUNE 2011
www.ti.com
Dual-Channel, 16-BIT, 1.25 GSPS Digital-to-Analog Converter (DAC)
Check for Samples: DAC3482
FEATURES
DESCRIPTION
•
The DAC3482 is a very low power, high dynamic
range, dual-channel, 16-bit digital-to-analog converter
(DAC) with a sample rate as high as 1.25 GSPS.
1
•
•
•
•
•
•
•
•
•
•
Very Low Power: 900 mW 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
– Fine Mixer with 32-bit NCO
– Power Saving Coarse Mixer: ± 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 LVDS Input Data Bus
– Word- or Byte-Wide Interface
– 8 Sample Input FIFO
– Data Pattern Checker
– Parity Check
Temperature Sensor
Differential Scalable Output: 10mA to 30mA
Space Saving Package: 88-pin 9x9mm WQFN
(GREEN / Pb-Free)
APPLICATIONS
•
•
•
Cellular Base Stations
Diversity Transmit
Wideband Communications
The device includes features that simplify the design
of complex transmit architectures: 2x to 16x digital
interpolation filters with over 90 dB of stop-band
attenuation simplify the data interface and
reconstruction filters. A complex mixer allows 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 flexible
LVDS data bus with on-chip termination. Data can be
input either word-wide or byte-wide. 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.
The DAC3482 very low power, small size, superior
crosstalk, high dynamic range and features are an
ideal fit for today’s communication systems.
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.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2011, Texas Instruments Incorporated
DAC3482
SLAS748A – MARCH 2011 – REVISED JUNE 2011
www.ti.com
DACCLKP
100
FRAMEP
FRAMEN
LVDS
x2
x2
59 taps
x2
x2
23 taps
FIR4
x2
11 taps
x2
11 taps
x2
QMC
I-offset
sin
FIR3
Complex Mixer
(FMIX or CMIX)
8 Sample FIFO
•
•
•
De-interleave
Programmable Delay
100
FIR2
x2
x
sin(x)
16-b
DACI
IOUTIN
I-Group
Delay
Q-Group
Delay
9 taps
x
sin(x)
16-b
DACQ
16
QMC
Q-offset
CMIX Control
(±n*Fs/8)
2x–16x Interpolation
IOUTIP
IOUTQP
IOUTQN
DAC
Gain
Frame Strobe and
Optional Parity
OSTRP
Temp
Sensor
Control Interface
LVPECL
TESTMODE
ALARM
SLEEP
RESETB
TXENABLE
SCLK
SDENB
SDO
SDIO
OSTRN
AVDD
IOVDD
SYNCN
LVDS
Pattern Test
•
•
•
LVDS
FIR1
16
100
SYNCP
FIR0
100
D0N
AVDD
32-Bit NCO
LVDS
•
•
•
D0P
DACVDD
VFUSE
LVDS
100
D15P
BIASJ
Programmable
Delay
cos
D15N
EXTIO
LVDS
GND
PARITYN
1.2-V
Reference
QMC
Gain and Phase
PARITYP
Clock Distribution
100
DATACLKN
DIGVDD
Low Jitter
PLL
LVPECL
DACCLKN
DATACLKP
LPF
CLKVDD
PLLAVDD
FUNCTIONAL BLOCK DIAGRAM
B0450-01
2
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DEVICE INFORMATION
PINOUT
RKD Package
GND
DACVDD
AVDD
EXTIO
IOUTQP
AVDD
IOUTQN
AVDD
GND
AVDD
C4
B32
A35
B31
A34
A1
B1
A2
B2
A3
B3
A4
B4
A5
B5
DAC3482
B6
88-WQFN 9mm x 9mm
A6
A7
B7
A8
B8
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
A14
B13
A15
B14
A16
B15
A17
B16
A18
B17
A19
B18
A20
B19
A21
B20
A22
A9
A12
B11
A13
B12
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
C1
B35
A38
B34
A37
B33
A36
TESTMODE
SLEEP
DACVDD
GND
AVDD
GND
AVDD
IOUTIN
AVDD
IOUTIP
DACVDD
(Top View)
BIASJ
RESETB
TXENABLE
ALARM
SCLK
SDENB
SDIO
SDO
PARITYN
PARITYP
DIGVDD
IOVDD
D0N
D0P
D1N
D1P
DIGVDD
D2N
D2P
D3N
D3P
C3
D9P
D9N
D8P
D8N
DATACLKP
DATACLKN
IOVDD
FRAMEP
FRAMEN
D7P
D7N
D6P
D6N
D5P
D5N
D4P
D4N
D11P
D11N
D10P
D10N
C2
P0133-01
PIN FUNCTIONS
PIN
NAME
NO.
I/O
DESCRIPTION
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 low, but can be changed to active high via config0 alarm_out_pol
control bit.
BIASJ
A33
O
Full-scale output current bias. For 30mA full-scale output current, connect 1.28kΩ 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 (continued)
PIN
NAME
NO.
I/O
DESCRIPTION
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) and can be transferred in either byte-wide or
word-wide mode. In byte-wide mode the unused pins can be left unconnected.
D[15..0]P
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.
DATACLKP
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).
DATACLKN
B15
I
LVDS negative input data clock. (See DATACLKP description)
DIGVDD
A6, A9, A25,
A28
I
Digital supply voltage. (1.2 V). It is recommended to isolate this supply from CLKVDD and DACVDD.
EXTIO
A34
I/O
FRAMEP
B16
I
LVDS frame indicator positive input. Internal 100 Ω termination resistor. The main functions of this
input are to reset the FIFO 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.
FRAMEN
A18
I
LVDS frame indicator negative input. (See the FRAMEP description)
GND
C1, C2, C3,
C4, B32,
B33, B38,
B39, Thermal
Pad
I
These pins are ground for all supplies.
IOUTIP
B36
O
I-Channel DAC current output. Connect directly to ground if unused.
IOUTIN
B37
O
I-Channel DAC complementary current output. Connect directly to ground if unused.
IOUTQP
B35
O
Q-Channel DAC current output. Connect directly to ground if unused.
IOUTQN
B34
O
Q-Channel DAC complementary current output. Connect directly to ground if unused.
IOVDD
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 to sync the divided-down clocks and FIFO output pointer in Dual Sync
Sources Mode. 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)
SCLK
A31
I
Serial interface clock. Internal pull-down.
SDENB
B28
I
Active low serial data enable, always an input to the DAC3482. Internal pull-up.
SDIO
A30
I/O
4
D15P is most significant data bit (MSB) in word-wide mode
D7P is most significant data bit (MSB) in byte-wide mode
D0P is least significant data bit (LSB)
The order of the bus can be reversed via config2 revbus bit.
Used as external reference input when internal reference is disabled through config27 extref_ena =
‘1’. Used as internal reference output when config27 extref_ena = ‘0’ (default). Requires a 0.1 μF
decoupling capacitor to AGND when used as reference output.
PLL loop filter connection. If not using the clock multiplying PLL, the LPF pin can be left unconnected.
Serial interface data. Bi-directional in 3-pin mode (default) and uni-directional in 4-pin mode. Internal
pull-down.
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PIN FUNCTIONS (continued)
PIN
NAME
I/O
NO.
DESCRIPTION
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.
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 “1” or pull CMOS
TXENABLE pin to high.
To disable analog output, set sif_txenable to “0” and pull CMOS TXENABLE pin to low. The digital
logic section is forced to all 0, and any input data is ignored.
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.
ORDERING INFORMATION (1)
TA
–40°C to 85°C
(1)
(2)
(3)
PACKAGE DRAWING/TYPE (2) (3)
TRANSPORT MEDIA
RKD / 88 WQFN Quad Flatpack No-Lead
Tape and Reel
ORDER CODE
DAC3482IRKDT
DAC3482IRKDR
QUANTITY
250
2000
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or visit the
device product folder at www.ti.com.
Thermal Pad Size: 6.4 mm x 6.4 mm
MSL Peak Temperature: Level-3-260C-168 HR
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted) (1)
VALUE
Supply voltage
range (2)
Pin voltage range (2)
UNIT
MIN
MAX
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
IOUTIP/N, IOUTQP/N
–1.0
AVDD + 0.5
V
EXTIO, BIASJ
–0.5
AVDD + 0.5
V
LPF
0.5
PLLAVDD+0.5V
V
20
mA
Peak input current (any input)
–30
mA
Operating free-air temperature range, TA: DAC3482
–40
85
°C
Storage temperature range
–65
150
°C
Peak total input current (all inputs)
(1)
(2)
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.
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THERMAL INFORMATION
DAC3482
THERMAL METRIC (1)
RKD PACKAGE
UNITS
(88) PINS
TJ
Maximum junction temperature
125
(2)
θJA
Junction-to-ambient thermal resistance
θJCtop
Junction-to-case (top) thermal resistance (3)
7.1
θJCbot
Junction-to-case (bottom) thermal resistance (4)
0.6
(5)
22.1
θJB
Junction-to-board thermal resistance
ψJT
Junction-to-top characterization parameter (6)
0.1
ψJB
Junction-to-board characterization parameter (7)
4.6
(1)
(2)
(3)
(4)
(5)
(6)
(7)
6
°C
4.7
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, high-K board, as
specified in JESD51-7, in an environment described in JESD51-2a.
The junction-to-case (top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific
JEDEC-standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.
The junction-to-case (bottom) thermal resistance is obtained by simulating a cold plate test on the exposed (power) pad. No specific
JEDEC standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.
The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB
temperature, as described in JESD51-8.
The junction-to-top characterization parameter, ψJT, estimates the junction temperature of a device in a real system and is extracted
from the simulation data for obtaining θJA, using a procedure described in JESD51-2a (sections 6 and 7).
The junction-to-board characterization parameter, ψJB, estimates the junction temperature of a device in a real system and is extracted
from the simulation data for obtaining θJA , using a procedure described in JESD51-2a (sections 6 and 7).
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ELECTRICAL CHARACTERISTICS – DC SPECIFICATIONS (1)
over recommended operating free-air temperature range, nominal supplies, IOUTFS = 20mA (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
Resolution
TYP MAX
UNIT
16
Bits
DC ACCURACY
DNL
Differential nonlinearity
INL
Integral nonlinearity
1 LSB = IOUTFS/216
±2
LSB
±4
LSB
ANALOG OUTPUT
±0.04
LSB
±0.001
%FSR
With external reference
±2
%FSR
With internal reference
±2
%FSR
With internal reference
±2
%FSR
Coarse gain linearity
Offset error
Mid code offset
Gain error
Gain mismatch
Full scale output current
10
20
–0.5
Output compliance range
Output resistance
Output capacitance
30
mA
0.6
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
0.6
External Reference Mode
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
POWER SUPPLY
PSRR
AVDD, IOVDD, PLLAVDD
3.14
3.3
3.46
V
CLKVDD, DACVDD, DIGVDD
1.14
1.2
1.26
V
Power supply rejection ratio
DC tested
±0.2
80
85
mA
MODE 1
fDAC = 1.25GSPS, 2x interpolation, Mixer on,
QMC on, invsinc on,
PLL enabled, 20mA FS output, IF = 200MHz
390
450
mA
30
50
mA
95
110
mA
882
980
mW
%FSR/V
POWER CONSUMPTION
I(AVDD)
Analog supply current (3)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
I(AVDD)
Analog supply current (3)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
(1)
(2)
(3)
MODE 2
fDAC = 1.25GSPS, 2x interpolation, Mixer on,
QMC on, invsinc on,
PLL disabled, 20mA FS output, IF = 200MHz
65
mA
385
mA
30
mA
70
mA
800
mW
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.
Includes AVDD, PLLAVDD, and IOVDD
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ELECTRICAL CHARACTERISTICS – DC SPECIFICATIONS(1) (continued)
over recommended operating free-air temperature range, nominal supplies, IOUTFS = 20mA (unless otherwise noted)
PARAMETER
TEST CONDITIONS
I(AVDD)
Analog supply current
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
I(AVDD)
Analog supply current (3)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
I(AVDD)
Analog supply current (3)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
I(AVDD)
I(DIGVDD)
Digital supply current
I(DACVDD)
DAC supply current
I(CLKVDD)
Clock supply current
P
Power dissipation
MODE 3
fDAC = 625MSPS, 2x interpolation, Mixer on,
QMC on, invsinc off,
PLL disabled, 20mA FS output, IF = 200MHz
MODE 4
fDAC = 1.25GSPS, 2x interpolation, Mixer on,
QMC on, invsinc on,
PLL enabled, I/Q output sleep, IF = 200MHz,
TYP MAX
UNIT
65
mA
190
mA
15
mA
45
mA
515
mW
35
mA
395
mA
30
mA
95
mA
740
mW
20
mA
10
mA
4
mA
10
mA
Power dissipation
95
mW
Analog supply current(3)
80
mA
200
mA
25
mA
Mode 5
Power-Down mode: No clock,
DAC on sleep mode (clock receiver sleep),
I/Q output sleep, static data pattern
Mode 6
fDAC = 1GSPS, 2x interpolation, Mixer off,
QMC off, invsinc off, PLL enabled, 20mA FS
output, IF = 200MHz
–40
Operating Range
8
MIN
(3)
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85
mA
636
mW
25
85
°C
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ELECTRICAL CHARACTERISTICS – DIGITAL SPECIFICATIONS
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
200
400
1000
mV
–200
mV
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
ZT
Internal termination
CL
LVDS Input capacitance
fINTERL
Interleaved LVDS data
transfer rate
fDATA
Input data rate
1.075
1.2
V
110
Ω
2
pF
1250
Word-wide interface mode
625
Byte-wide interface mode
312.5
MSPS
MSPS
CLOCK INPUT (DACCLKP/N)
Duty cycle
40%
Differential voltage (2)
0.4
60%
1.0
DACCLKP/N input
frequency
V
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%
Differential voltage
0.4
1.0
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
VOL
(1)
(2)
ALARM, SDO, SDIO
ALARM, SDO, SDIO
2
V
0.8
V
40
µA
40
µA
2
Iload = –100 μA
IOVDD – 0.2
Iload = –2 mA
0.8 x IOVDD
pF
V
V
Iload = 100 μA
0.2
V
Iload = 2 mA
0.5
V
See LVDS INPUTS section for terminology.
Driving the clock input with a differential voltage lower than 1 V may result in degraded performance.
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ELECTRICAL CHARACTERISTICS – DIGITAL SPECIFICATIONS (continued)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DIGITAL INPUT TIMING SPECIFICATIONS
Timing LVDS inputs: D[15:0]P/N, FRAMEP/N, SYNCP/N, PARITYP/N, double edge latching
Config36 Setting
Setup time, D[15:0]P/N,
FRAMEP/N, SYNCP/N
and PARITYP/N, valid to
either edge of
DATACLKP/N
ts(DATA)
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
ps
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)
10
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
0
fDATACLK is DATACLK frequency in MHz
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1/2fDATACLK
ps
ns
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ELECTRICAL CHARACTERISTICS – DIGITAL SPECIFICATIONS (continued)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
TIMING OUTPUT STROBE INPUT: DACCLKP/N rising edge LATCHING (3)
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
0
ps
300
ps
(4)
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
t(SCLK)
Period of SCLK
1
µs
100
ns
td(Data)
Data output delay after
falling edge of SCLK
10
ns
tRESET
Minimum RESETB pulse
width
25
ns
(3)
(4)
Register config6 read (temperature sensor read)
All other registers
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 to provide the DACCLK and OSTR signals to all the DAC3482 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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ELECTRICAL CHARACTERISTICS – AC SPECIFICATIONS
over recommended operating free-air temperature range, nominal supplies, IOUTFS = 20mA (unless otherwise noted)
PARAMETER
TEST CONDITIONS / COMMENTS
MIN
TYP
MAX
UNIT
ANALOG OUTPUT (1)
fDAC
Maximum DAC rate
ts(DAC)
Output settling time to 0.1%
Transition: Code 0x0000 to 0xFFFF
1250
tpd
Output propagation delay
DAC outputs are updated on the falling edge of DAC clock. Does not include
Digital Latency (see below).
tr(IOUT)
tf(IOUT)
ns
2
ns
Output rise time 10% to 90%
220
ps
Output fall time 90% to 10%
220
ps
8-bit
interface
Digital latency
16-bit
interface
Powerup
Time
MSPS
10
No interpolation, FIFO enabled, Mixer off, QMC off, Inverse
sinc off
250
2x Interpolation
212
4x Interpolation
372
8x Interpolation
723
16x Interpolation
1440
No interpolation, FIFO enabled, Mixer off, QMC off, Inverse
sinc off
140
2x Interpolation
228
4x Interpolation
417
8x Interpolation
817
16x Interpolation
1630
Fine mixer
24
QMC
16
Inverse sinc
20
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
AC PERFORMANCE (2)
SFDR
IMD3
NSD
Spurious free dynamic range
(0 to fDAC/2) tone at 0 dBFS
Third-order two-tone
intermodulation distortion
Each tone at –12 dBFS
12
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
79
fDAC = 1.25 GSPS, fOUT = 100 ± 0.5 MHz
77.5
Noise spectral density
Tone at 0dBFS
fDAC = 1.25 GSPS, fOUT = 10 MHz
160
fDAC = 1.25 GSPS, fOUT = 80 MHz
155
Adjacent channel leakage ratio,
single carrier
fDAC = 1.2288 GSPS, fOUT = 30.72 MHz
77
fDAC = 1.2288 GSPS, fOUT = 153.6 MHz
74
Alternate channel leakage ratio,
single carrier
fDAC = 1.2288 GSPS, fOUT = 30.72 MHz
82
fDAC = 1.2288 GSPS, fOUT = 153.6 MHz
80
Channel isolation
fDAC = 1.25 GSPS, fOUT = 10 MHz
84
ACLR (3)
(1)
(2)
(3)
fDAC = 1.25 GSPS, fOUT = 20 MHz
dBc
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
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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
40k
50k
60k
G002
0
100
200
300
400
Output Frequency (MHz)
500
80
70
60
50
40
30
600
0 dBFS
−6 dBFS
−12 dBFS
90
0
100
G003
Figure 3. SFDR vs Output Frequency Over Input Scale
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)
30k
Code
100
0 dBFS
−6 dBFS
−12 dBFS
90
70
60
70
60
50
50
40
40
30
20k
Figure 2. Differential Nonlinearity
100
30
10k
G001
0
100
200
300
400
Output Frequency (MHz)
500
600
30
0
G005
Figure 5. Third Harmonic Distortion vs
Output Frequency Over Input Scale
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
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
−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)
150
200
250
300
Output Frequency (MHz)
0
Power (dBm)
−20
−90
600
10
G011
Figure 11. Single Tone Spectral Plot
14
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
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110
210
310
410
Frequency (MHz)
510
610
G012
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)
G014
fDAC = 600 MSPS
fDAC = 800 MSPS
fDAC = 1000 MSPS
fDAC = 1250 MSPS
60
50
40
500
30
600
0
100
G015
200
300
400
Output Frequency (MHz)
500
600
G016
Figure 16. IMD3 vs Output Frequency Over fDAC
100
0
NCO Bypassed
QMC Bypassed
fDAC = 1250 MSPS
fOUT = 70 MHz
Tone Spacing = 1 MHz
−10
90
−20
80
−30
Power (dBm)
IMD3 (dBc)
600
70
Figure 15. IMD3 vs Output Frequency Over Interpolation
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
30
500
Figure 14. IMD3 vs Output Frequency Over Input Scale
IMD3 (dBc)
IMD3 (dBc)
Figure 13. Single Tone Spectral Plot
50
0
G013
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
66
67
68
69
70
71
72
Frequency (MHz)
73
74
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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
155
160
500
600
G020
150
145
155
150
145
140
140
135
135
0
100
200
300
400
Output Frequency (MHz)
500
130
600
0
100
G021
Figure 21. NSD vs Output Frequency Over Interpolation
200
300
400
Output Frequency (MHz)
500
600
G022
Figure 22. NSD vs Output Frequency Over fDAC
170
170
IOUTFS = 10 mA w/ 4:1 Transformer
IOUTFS = 20 mA w/ 4:1 Transformer
IOUTFS = 30 mA w/ 2:1 Transformer
165
160
155
150
145
155
150
145
140
140
135
135
0
50
100
150
200
250
300
Output Frequency (MHz)
350
PLL Bypassed
PLL Enabled w/ PFD of 78.125 MHz
165
NSD (dBc/Hz)
160
NSD (dBc/Hz)
200
300
400
Output Frequency (MHz)
fDAC = 600 MSPS
fDAC = 800 MSPS
fDAC = 1000 MSPS
fDAC = 1250 MSPS
165
NSD (dBc/Hz)
160
400
130
0
G023
Figure 23. NSD vs Output Frequency Over IOUTFS
16
100
170
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
165
130
0
Figure 20. NSD vs Output Frequency Over Input Scale
170
NSD (dBc/Hz)
155
140
−80
130
0 dBFS
−6 dBFS
−12 dBFS
165
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
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
18
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)
800
800
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
600
500
400
300
Bandbase Input = 5 MHz
NCO Disabled
QMC Disabled
CMIX Disabled
200
100
0
0
200
400
600
800
fDAC (MSPS)
1000
300
200
Bandbase Input = 0 MHz
NCO Enabled w/ 5 MHz Mixing
QMC Enabled
0
200
400
600
800
1000
1200
fDAC (MSPS)
G038
Figure 38. Power Consumption vs fDAC Over Interpolation
500
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
450
DIGVDD Current (mA)
Power Consumption (mW)
400
G037
NCO Enabled
QMC Enabled
70
60
50
40
30
20
400
350
Bandbase Input = 5 MHz
NCO Disabled
QMC Disabled
CMIX Disabled
300
250
200
150
100
10
50
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
400
80
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
300
250
200
150
100
Bandbase Input = 0 MHz
NCO Enabled w/ 5 MHz Mixing
QMC Enabled
50
0
200
400
NCO Enabled
QMC Enabled
70
DIGVDD Current (mA)
350
DIGVDD Current (mA)
500
0
1200
80
0
600
100
Figure 37. Power Consumption vs fDAC Over Interpolation
0
1x Interpolation
2x Interpolation
4x Interpolation
8x Interpolation
16x Interpolation
700
Power Consumption (mW)
Power Consumption (mW)
700
600
800
fDAC (MSPS)
1000
60
50
40
30
20
10
0
1200
0
G041
Figure 41. DIGVDD Current vs fDAC Over 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
100
120
90
110
80
100
70
60
50
40
30
1000
20
30
1200
0
G045
Figure 45. AVDD Current vs fDAC
G044
60
40
600
800
fDAC (MSPS)
1200
70
50
400
1000
80
10
200
600
800
fDAC (MSPS)
90
20
0
400
Figure 44. CLKVDD Current vs fDAC
Isolation Level (dBc)
AVDD Current (mA)
Figure 43. DACVDD Current vs fDAC
0
200
G043
50
100
150
Output Frequency (MHz)
200
250
G046
Figure 46. Isolation Level vs Output Frequency
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DEFINITION OF SPECIFICATIONS
Adjacent Carrier Leakage Ratio (ACLR): Defined for a 3.84Mcps 3GPP W-CDMA input signal measured in a
3.84MHz bandwidth at a 5MHz 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 1Hz bandwidth within the first Nyquist zone.
SERIAL INTERFACE
The serial port of the DAC3482 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 DAC3482. 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 below 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
MSB
Bit
Description
7
R/W
LSB
6
A6
5
A5
4
A4
3
A3
2
A2
1
A1
0
A0
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R/W
Identifies the following data transfer cycle as a read or write operation. A high indicates a read
operation from DAC3482 and a low indicates a write operation to DAC3482.
[A6 : A0]
Identifies the address of the register to be accessed during the read or write operation.
22
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Figure 47 shows the serial interface timing diagram for a DAC3482 write operation. SCLK is the serial interface clock input to DAC3482. Serial data
enable SDENB is an active low input to DAC3482. SDIO is serial data in. Input data to DAC3482 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 47. Serial Interface Write Timing Diagram
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Figure 48 shows the serial interface timing diagram for a DAC3482 read operation. SCLK is the serial interface clock input to DAC3482. Serial data
enable SDENB is an active low input to DAC3482. SDIO is serial data in during the instruction cycle. In 3 pin configuration, SDIO is data out from the
DAC3482 during the data transfer cycle, while SDO is in a high-impedance state. In 4 pin configuration, SDO is data out from the DAC3482 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.
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 48. Serial Interface Read Timing Diagram
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Table 2. Register Map (1)
Name
Address
Default
(MSB)
Bit 15
Bit 14
Bit 13
Bit 12
config0
0x00
0x049C
qmc_offset_
ena
reserved
qmc_corr_
ena
reserved
Bit 11
Bit 10
Bit 9
Bit 8
interp(3:0)
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
invsinc_ena
reserved
alarm_
1away_
ena
alarm_
collision_
ena
reserved
reserved
twos
reserved
config1
0x01
0x050E
iotest_ena
reserved
reserved
64cnt_
ena
oddeven_
parity
word_
parity_
ena
config2
0x02
0x7000
16bit_in
dacclk
gone_ena
dataclk
gone_ena
collision_
gone_ena
resreved
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
reserved
reserved
config11
0x0B
0x0000
reserved
reserved
reserved
config12
0x0C
0x0400
reserved
reserved
reserved
config13
0x0D
0x0400
config14
0x0E
0x0400
config15
0x0F
0x0400
config16
0x10
0x0000
reserved
reserved
reserved
reserved
config17
0x11
0x0000
reserved
reserved
reserved
reserved
config18
0x12
0x0000
config19
0x13
0x0000
reserved
config20
0x14
0x0000
phase_add(15:0)
config21
0x15
0x0000
phase_add(31:16)
config22
0x16
0x0000
reserved
config23
0x17
0x0000
config24
0x18
NA
config25
0x19
0x0440
config26
0x1A
0x0020
config27
0x1B
0x0000
config28
0x1C
0x0000
config29
0x1D
0x0000
config30
0x1E
0x1111
(1)
coarse_dac(3:0)
frame_
parity_e
na
reserved
reserved
dacI_
complement
dacQ_
complement
reserved
alarm_
2away_
ena
reserved
reserved
sif4_ena
mixer_ena
mixer_gain
nco_ena
revbus
reserved
reserved
sif_txenable
iotest_results(15:0)
alarm_
from_
zerochk
reserved
alarm_
dacclk_
gone
alarms_from_fifo(2:0)
alarm_
dataclk_
gone
alarm_
output_
gone
alarm_
from _
iotest
alarm_
from_pll
reserved
tempdata(7:0)
alarm_
rparity
alarm_
fparity
alarm_
frame_parity
reserved
reserved
reserved
reserved
reserved
alarms_mask(15:0)
reserved
reserved
reserved
qmc_offsetI(12:0)
fifo_offset(2:0)
qmc_offsetQ(12:0)
reserved
reserved
reserved
cmix(3:0)
reserved
reserved
output_delay (1:0)
reserved
reserved
reserved
reserved
qmc_gainI(10:0)
reserved
qmc_gainQ(10:0)
reserved
reserved
reserved
reserved
qmc_phase(11:0)
reserved
phase_offset(15:0)
reserved
reserved
pll_reset
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
pll_p(2:0)
fuse_
sleep
reserved
reserved
reserved
bias_
sleep
reserved
reserved
reserved
tsense_
sleep
reserved
pll_sleep
reserved
pll_vcoitune(2:0)
clkrecv_
sleep
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
syncsel_qmoffset(3:0)
pll_lfvolt(2:0)
reserved
reserved
syncsel_qmcorr(3:0)
reserved
Unless otherwise noted, all reserved registers should be programmed to default values.
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Table 2. Register Map(1) (continued)
(MSB)
Bit 15
Name
Address
Default
Bit 14
Bit 13
Bit 12
Bit 11
config31
0x1F
0x1140
syncsel_mixer(3:0)
reserved
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 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
syncsel_nco(3:0)
Bit 2
syncsel_dataformatter
Bit 1
(LSB)
Bit 0
sif_sync
reserved
clkdiv_
sync_sel
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
sleep_cntl(15:0)
datadly(2:0)
clkdly(2:0)
reserved
iotest_pattern7
reserved
ostrtodig_
sel
config45
0x2D
0x0004
config46
0x2E
0x0000
reserved
config47
0x2F
0x0000
grp_delayQ(7:0)
config48
0x30
0x0000
version
0x7F
0x5409
26
Bit 10
ramp_ena
reserved
sifdac_ena
grp_delayI(7:0)
reserved
sifdac(15:0)
reserved
reserved
reserved
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deviceid(1:0)
versionid(2:0)
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REGISTER DESCRIPTIONS
Register name: config0 – Address: 0x00, Default: 0x049C
Register
Name
Address
Bit
config0
0x00
15
qmc_offset_ena
When set, the digital Quadrature Modulator Correction (QMC) offset
correction is enabled.
0
14
Reserved
Reserved for factory use.
0
13
qmc_corr_ena
When set, the QMC phase and gain correction circuitry is enabled.
0
12
Reserved
Reserved for factory use.
11:8
interp(3:0)
These bits define the interpolation factor
Name
Default
Value
Function
0
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. See the Power-Up
Sequence section for more detail.
1
1
invsinc_ena
When set, the inverse sinc filter is enabled.
0
0
Reserved
Reserved for factory use.
0
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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
Reserved
Reserved for factory use.
Note: Default value is ‘1’. Must be set to ‘0’ for proper operation
1
7
Reserved
Reserved for factory use.
0
6
dacI_complement
When set, the DACI output is complemented. This allows to
effectively change the + and – designations of the LVDS data lines.
0
5
dacQ_complement
When set, the DACQ output is complemented. This allows to
effectively change the + and – designations of the LVDS data lines.
0
4
Reserved
Reserved for factory use.
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
28
Name
Default
Value
Function
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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 "0").
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 "0").
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 "0").
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 2’s complement.
When cleared, the input is expected to be offset-binary.
0
0
Reserved
Reserved for factory use.
0
Name
Default
Value
Function
Register name: config3 – Address: 0x03, Default: 0xF000
Register
Name
Address
Bit
config3
0x03
15:12
Name
coarse_dac(3:0)
Default
Value
Function
Scales the output current in 16 equal steps.
IFS =
1111
VEXTIO
´ 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 “1”.
To enable analog output data transmission, set sif_txenable to “1” or
pull CMOS TXENABLE pin (A32) to high. To disable analog output,
set sif_txenable to “0” and pull CMOS TXENABLE pin (A32) to low.
0
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Register name: config4 – Address: 0x04, Default: No RESET Value (WRITE TO CLEAR)
Register
Name
Address
Bit
config4
0x04
15:0
Name
Function
iotest_results(15:0)
This register is used with pattern checker test enabled (iotest_ena in config1,
bit<15> set to “1”). It does not have a default RESET value.
Default
Value
No 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].
Register name: config5 – Address: 0x05, Default: Setup and Power-Up Conditions Dependent (WRITE TO
CLEAR)
Register
Name
Address
config5
0x05
Bit
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. Refer to the Power-Up
Sequence section 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 "100" 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
30
Name
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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 1μs.
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
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_lparity
2
alarm_frame_parity
1
not used
0
not used
0xFFFF
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_offsetI(12:0)
DACI 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 config8 should be written last. Programming
config9 will not affect the offset setting.
12:0
Name
Default
Value
Function
0
All zeros
Register name: config9 – Address: 0x09, Default: 0x8000
Register
Name
Address
config9
0x09
Bit
Name
Default
Value
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
DACQ offset correction. The offset is measured in DAC LSBs.
qmc_offsetQ(12:0)
100
All zeros
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Register name: config10 – Address: 0x0A, Default: 0x0000
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.
0
12:0
Reserved
Reserved for factory use.
All zeros
Name
Default
Value
Function
Register name: config11 – Address: 0x0B, Default: 0x0000
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.
0
12:0
Reserved
Reserved for factory use.
All zeros
Name
Default
Value
Function
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_gainI(10:0)
QMC gain for DACI. The full 11-bit qmc_gainI(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
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_gainQ(10:0)
QMC gain for DACQ. 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
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.
0
10:0
Reserved
Reserved for factory use.
10000000
000
32
Name
Function
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Value
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Register name: config15 – Address: 0x0F, Default: 0x0400
Register
Name
Address
Bit
config15
0x0F
15:14
output_ delay(1:0)
Delays the DAC outputs from 0 to 3 DAC clock cycles.
00
13:12
Reserved
Reserved for factory use.
00
11
Reserved
Reserved for factory use.
0
10:0
Reserved
Reserved for factory use.
10000000
000
Name
Default
Value
Function
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
Reserved
Reserved for factory use. Note: Default value is ‘0’. Must be set to ‘1’ for proper
operation
0
12
Reserved
Reserved for factory use. Note: Default value is ‘0’. Must be set to ‘1’ for proper
operation
0
qmc_phase(11:0)
QMC correction phase. The 12-bit qmc_phase(11:0) word is formatted as two’s
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 offset registers (config12, config13, and config16) into the
QMC block at the same time. When updating the QMC values config16 should
be written last. Programming config12 and config13 will not affect the QMC
settings.
All zeros
11:0
Name
Default
Value
Function
Register name: config17 – Address: 0x11, Default: 0x0000
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.
0
11:0
Reserved
Reserved for factory use.
All zeros
Name
Default
Value
Function
Register name: config18 – Address: 0x12, Default: 0x0000 (CAUSES AUTO-SYNC)
Register
Name
Address
Bit
config18
0x12
15:0
Name
phase_offset(15:0)
Default
Value
Function
Phase offset added to the 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 Qfine 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.
0x0000
Register name: config19 – Address: 0x13, Default: 0x0000
Register
Name
Address
Bit
config19
0x13
15:0
Name
Reserved
Function
Reserved for factory use.
Default
Value
0x0000
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Register name: config20 – Address: 0x14, Default: 0x0000
Register
Name
Address
Bit
config20
0x14
15:0
Name
phase_ add(15:0)
Default
Value
Function
The phase_add(15:0) value is used to determine the NCO frequency. The two’s
complement formatted value can be positive or negative. Each LSB represents
Fs/(2^32) frequency step.
0x0000
Register name: config21 – Address: 0x15, Default: 0x0000
Register
Name
Address
Bit
config21
0x15
15:0
Name
phase_ add(31:16)
Default
Value
Function
See config20 above.
0x0000
Register name: config22 – Address: 0x16, Default: 0x0000
Register
Name
Address
Bit
config22
0x16
15:0
Name
Reserved
Default
Value
Function
Reserved for factory use.
0x0000
Register name: config23 – Address: 0x17, Default: 0x0000
Register
Name
Address
Bit
config23
0x17
15:0
Name
Reserved
Default
Value
Function
Reserved for factory use.
0x0000
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 0V. Toggle from ‘1’ to ‘0’ 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
34
Name
Function
Default
Value
001
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 0.4125V.
The entire range covers from 0V to 3.3V. The optimal lock range of the PLL will be
from 010 to 101 (i.e. 0.825V to 2.063V). Adjust pll_vco(5:0) for optimal lock range.
NA
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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. (i.e. 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. (i.e. 0, 2, 4, and 6 are not valid. M divider has even values only.)
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
3:2
pll_vcoitune(1:0)
PLL VCO bias tuning bits. Set to "01" for normal PLL operation.
00
1:0
Reserved
Reserved for factory use.
00
Name
Default
Value
Function
00000100
0100
Register name: config26 – Address: 0x1A, Default: 0x0020
Register
Name
Address
Bit
config26
0x1A
15:10
Name
Default
Value
Function
pll_vco(6:0)
VCO frequency coarse tuning bits.
9
Reserved
Reserved for factory use.
000000
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
Reserved
Reserved for factory use.
0
2
Reserved
Reserved for factory use.
0
1
Reserved
Reserved for factory use.
0
0
Reserved
Reserved for factory use.
0
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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
Puts the fuses to sleep when set high.
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.
0
5:0
Reserved
Reserved for factory use.
000000
Name
Function
Default
Value
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
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
Default
Value
Function
Register name: config30 – Address: 0x1E, Default: 0x1111
Register
Name
Address
Bit
config30
0x1E
15:12
syncsel_qmoffset(3:0)
Selects the syncing source(s) of the double buffered QMC offset registers. 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: SYNC
MM Bit 13: OSTR
MM Bit 12: Auto-sync from register write
0001
11:8
Reserved
Reserved for factory use.
0001
7:4
syncsel_qmcorr(3:0)
Selects the syncing source(s) of the 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
Reserved
Reserved for factory use.
0001
36
Name
Function
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Value
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Register name: config31 – Address: 0x1F, Default: 0x1140
Register
Name
Address
Bit
config31
0x1F
15:12
syncsel_mixer(3:0)
Selects the syncing source(s) of the double buffered mixer registers. 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: SYNC
MM Bit 13: OSTR
MM Bit 12: Auto-sync from register write
0001
11:8
Reserved
Reserved for factory use.
0001
7:4
syncsel_nco(3:0)
Selects the syncing source(s) of the two NCO accumulators. 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: FRAME
0100
3:2
syncsel_dataformatter
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 ‘1’ to cause a sync and then clear to ‘0’ to
remove it.
0
0
Reserved
Reserved for factory use.
0
Name
Default
Value
Function
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 ‘1’ 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>)
Register name: config33 – Address: 0x21, Default: 0x0000
Register
Name
Address
Bit
config33
0x21
15:0
Name
Reserved
Function
Reserved for factory use.
Default
Value
0x0000
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Register name: config34 – Address: 0x22, Default: 0x1B1B
Register
Name
Address
Bit
config34
0x22
15:14
Reserved
Reserved for factory use.
00
13:12
Reserved
Reserved for factory use.
01
11:10
Reserved
Reserved for factory use.
10
9:8
Reserved
Reserved for factory use.
11
7:6
Reserved
Reserved for factory use.
00
5:4
Reserved
Reserved for factory use.
01
3:2
Reserved
Reserved for factory use.
10
1:0
Reserved
Reserved for factory use.
11
Name
Default
Value
Function
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) to different blocks. When a
bit is set, the SLEEP signal will be sent to the corresponding block. These bits do not
override the SIF bits in register config26.
sleep_cntl(bit)
0xFFFF
Function
15
reserved
14
DACI sleep
13
DACQ sleep
12
reserved
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
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 40 ps
MM 0: Minimum
000
12:10
clkdly(2:0)
Controls the delay of the data clock through the LVDS receivers. Each LSB adds
approximately 40 ps
MM 0: Minimum
000
9:0
Reserved
Reserved for factory use.
Name
Default
Value
Function
0x000
Register name: config37 – Address: 0x25, Default: 0x7A7A
Register
Name
Address
Bit
config37
0x25
15:0
Name
iotest_pattern0
Default
Value
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.
0x7A7A
Register name: config38 – Address: 0x26, Default: 0xB6B6
Register
Name
Address
Bit
config38
0x26
15:0
38
Name
iotest_pattern1
Default
Value
Function
Dataword1 in the IO test pattern. It is used with the seven other words to test the input data.
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Register name: config39 – Address: 0x27, Default: 0xEAEA
Register
Name
Address
Bit
config39
0x27
15:0
Name
iotest_pattern2
Default
Value
Function
Dataword2 in the IO test pattern. It is used with the seven other words to test the input
data.
0xEAEA
Register name: config40 – Address: 0x28, Default: 0x4545
Register
Name
Address
Bit
config40
0x28
15:0
Function
Default
Value
Dataword3 in the IO test pattern. It is used with the seven other words to test the input data.
0x4545
Name
iotest_pattern3
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
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
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
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
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.
0
0000
0000
0100
0
Register name: config46 – Address: 0x2E, Default: 0x0000
Register
Name
Address
Bit
config46
0x2E
15:8
Reserved
Reserved for factory use.
0x00
7:0
grp_delayI(7:0)
Sets the group delay function for DACI. The maximum delay ranges from 30ps to
100ps and is dependent on DAC sample clock. Contact TI for specific application
information.
0x00
Name
Default
Value
Function
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Register name: config47 – Address: 0x2F, Default: 0x0000
Register
Name
Address
Bit
config47
0x2F
15:8
grp_delayQ(7:0)
Sets the group delay function for DACQ. The maximum delay ranges from 30ps to
100ps and is dependent on DAC sample clock. Contact TI for specific application
information.
0x00
7:0
Reserved
Reserved for factory use.
0x00
Name
Function
Default
Value
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
Register name: version– Address: 0x7F, Default: 0x5409 (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 ‘01’ for DAC3482.
01
2:0
versionid(2:0)
A hardwired register that contains the version of the chip.
100
40
Name
Function
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Default
Value
010101
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DATA INTERFACE
The DAC3482 has a 16-bit LVDS bus that accepts 16-bit I and Q data in either word-wide or byte-wide formats.
In word-wide mode data is sent through a 16-bit bus while in byte-wide mode an 8-bit bus is used. 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 3.
Table 3. LVDS Bus Input Assignment
(1)
Input Mode
Pins
Word-wide
D[15..0]
Byte-wide (1)
D[7..0]
The unused pins can be left floating. For word-by-word parity and IO
pattern checker functionality, the pins need to have known logic
values for valid functionality.
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
pulse-width (t(FRAME_SYNC)) needs to be at least equal to ½ 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 “1”. Refer to “Parity
Check Test” section for more detail
WORD-WIDE FORMAT
The word-wide format is selected by setting 16bit_in to “1” in the config2 register. In this mode the 16-bit data for
channels I and Q is word-wide interleaved in the form I0, Q0, I1, Q1… into the D[15:0] 16-bit bus. Data into the
DAC3482 is formatted according to the diagram shown in Figure 49 where index 0 is the data LSB and index 15
is the data MSB.
SAMPLE 0
D[15:0]P/N
I0
[15:0]
Q0
[15:0]
SAMPLE 1
I1
[15:0]
Q1
[15:0]
SAMPLE 2
I2
[15:0]
Q2
[15:0]
SAMPLE 3
I3
[15:0]
Q3
[15:0]
DATACLKP/N (DDR)
t(FRAME_SYNC)
Sync
Option #1
FRAMEP/N
Optional
Parity Bit
t(FRAME_SYNC)
Sync
Option #2
SYNCP/N
T0523-01
Figure 49. Word-Wide Data Transmission Format
For word-wide format only. The FIFO read and write pointers can also be synced by SIF SYNC as the third
option if multi-device synchronization is not needed. In this sync mode, syncsel_data_formatter(1:0) in register
config32 can be set to "10" or "11". The syncsel_fifoin(3:0) and syncsel_fifoout(3:0) in register config32 need to
be both set to "1000" for the SIF SYNC option.
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BYTE-WIDE FORMAT
The byte-wide format is selected by setting 16bit_in to “0” in the config2 register. In this mode the 16-bit data for
channels I and Q is byte-wide interleaved in the form I0[15:8], I0[7:0], Q0[15:8], Q0[7:0], I1[15:8]… into the D[7:0]
8-bit bus. Data into the DAC3482 is formatted according to the diagram shown in Figure 50 where index 0 is the
data LSB and index 15 is the data MSB. A rising edge transition of the sync signal, either FRAME or SYNC, is
used to establish the correct sample boundaries.
SAMPLE 0
D[7:0]P/N
I0
[15:8]
I0
[7:0]
Q0
[15:8]
SAMPLE 1
Q0
[7:0]
I1
[15:8]
I1
[7:0]
Q1
[15:8]
Q1
[7:0]
DATACLKP/N (DDR)
t(FRAME_SYNC)
Sync
Option #1
FRAMEP/N
Optional
Parity Bit
t(FRAME_SYNC)
Sync
Option #2
SYNCP/N
T0524-01
Figure 50. Byte-Wide Data Transmission Format
INPUT FIFO
The DAC3482 includes a 2-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.
Figure 51 shows a simplified block diagram of the FIFO.
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Clock Handoff
I-Data, 16-Bit
Frame Align
Q-Data, 16-Bit
0 ... 7
Write Pointer
Initial
Position
DATA
Output Side
Clocked by FIFO Out Clock
Word Wide Mode: DACCLK/2/Interpolation Factor
Byte Wide Mode: DACCLK/Interpolation Factor
FIFO:
2 x 16-Bits Wide
8-Samples deep
FRAME/
SYNC
Write Pointer Reset
32-Bit
0
Sample 0
I0[15:0], Q0[15:0]
0
1
Sample 1
I1[15:0], Q1[15:0]
1
2
Sample 2
I2[15:0], Q2[15:0]
2
3
Sample 3
I3[15:0], Q3[15:0]
3
4
Sample 4
I4[15:0], Q4[15:0]
4
5
Sample 5
I5[15:0], Q5[15:0]
5
6
Sample 6
I6[15:0], Q6[15:0]
6
7
Sample 7
I7[15:0], Q7[15:0]
7
FIFO Reset
16-Bit
32-Bit
0 ... 7
Read Pointer
Input Side
Clocked by DATACLK
FIFO I Output
16-Bit
FIFO Q Output
Initial
Position
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 Source Mode): OSTR resets read
pointer. Allows Multi-DAC synchronization
B0451-01
Figure 51. DAC3482 FIFO Block Diagram
Data is written to the device on the rising and falling edges of DATACLK. Each 32-bit wide sample (16-bit I-data
and 16-bit Q-data) 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 32-bits at a time from the address indicated by the read pointer. The FIFO
Out Clock is generated internally from the DACCLK signal. Its rate is equal to DACCLK/2/Interpolation for
word-wide data transmission, or DACCLK/Interpolation for byte-wide data transmission. 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 51. 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 config3 (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 is 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.
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, the 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. This limits the precise control of the output timing and makes full synchronization of multiple
devices difficult.
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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 to provide the DACCLK and OSTR signals to all the
DAC3482 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, the
signals to sync the FIFO read and write pointer can repeat at multiples of 8 FIFO samples when the data
interface is byte-wide format. When the data interface is word-wide format, the signal to sync the FIFO read and
write pointer can repeat at multiples of 16 FIFO samples.
The frequency limitation for FRAME and SYNC signals are the following:
fsync = fDATACLK/(n x 16) where n = 1, 2, … can repeat multiples of 8 FIFO samples for Byte-Wide Mode
fsync = fDATACLK/(n x 16) where n = 1, 2, … can repeat multiples of 16 FIFO samples for Word-Wide Mode
The frequency limitation for the OSTR signal is the following:
fOSTR = fDAC/(n x interpolation x 8) where n = 1, 2, … can repeat multiples of 8 FIFO samples for Byte-Wide
Mode
fOSTR = fDAC/(n x interpolation x 16) where n = 1, 2, … can repeat multiples of 16 FIFO samples for
World-Wide Mode
The frequencies above are at maximum when n = 1. This is when the FRAME, SYNC, or OSTR have a rising
edge transition every 8 or 16 FIFO samples. The occurrence can be made less frequent by setting n > 1, for
example, every n × 8 or n × 16 FIFO samples.
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
1x 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)
T0525-01
Figure 52. FIFO Write and Read Descriptions (Example shown with Word-Wide Mode)
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FIFO MODES OF OPERATION
The DAC3482 input FIFO can be completely bypassed through registers config0 and config32. The register
configuration for each mode is described in Table 4.
Register
Control Bits
config0
fifo_ena
config32
syncsel_fifoout(3:0)
Table 4. FIFO Operation Modes
config0 and config32 FIFO Bits
FIFO Mode
Dual Sync Sources
fifo_ena
syncsel_fifoout
Bit 3: sif_sync
Bit 2: OSTR
0
1
0
0
1 or 0 Depends on the
sync source
X
1
Bit 1: FRAME
Single Sync
Source
1
0
0
1 or 0 Depends on the sync
source
Bypass
0
X
X
X
Bit 0: SYNC
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.
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. This mode has a possibility of up to 2 DAC clocks offset between the multiple
DAC outputs. Applications requiring exact output timing control will need Dual Sync Sources mode instead of
Single Sync Source Mode. A single 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.
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 this constraint this mode is not
recommended. In bypass mode the pointers have no effect on the data path or handoff.
CLOCKING MODES
The DAC3482 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 DAC3482
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.
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16-Bit
DACI
PLL
DACCLK
Clock Distribution
to Digital
VCO/
Dividers
16-Bit
DACQ
pll_ena
B0452-01
Figure 53. Top Level Clock Diagram
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 DAC3482 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 “0” to bypass the PLL circuitry.
2. pll_sleep bit in register config26 to “1” to put the PLL and VCO into sleep mode.
PLL MODE
In this mode the clock at the DACCLK input functions as a reference clock source to the on-chip PLL. The
on-chip PLL will then multiply this reference clock to supply a higher frequency DAC sample rate clock. Figure 54
shows the block diagram of the PLL circuit.
OSTR (Internally Generated)
External Loop
Filter
DACCLKP
REFCLK
DACCLKN
PFD
and
CP
N
Divider
SYNCP
SYNC_PLL
Prescaler
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 54. PLL Block Diagram
The DAC3482 PLL mode is selected by setting the following:
1. pll_ena bit in register config24 to “1” to route to the PLL clock path.
2. pll_sleep bit in register config26 to “0” to enable the PLL and VCO.
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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 55 shows a typical relationship between coarse tune bits and VCO center
frequency.
4000
Coarse Tune Bits @
VCO Frequency (MHz)
3900
VCO Frequency (MHz ) - 3253
11.6
3800
3700
3600
3500
3400
3300
0
8
16
32
24
40
48
56
64
Coarse Tuning Bits
G047
Figure 55. Typical PLL/VCO Lock Range vs Coarse Tuning Bits
Common wireless infrastructure frequencies (614.4MHz, 737.28MHz, 1.2288GHz, etc.) are generated from this
VCO frequency in conjunction with the pre-scaler setting as shown in Table 5.
Table 5. 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 6. 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
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When the overall divide ratio is greater than 120, an external loop filter is required to ensure loop stability
The single charge pump current option is selected by setting pll_cp in register config24 to “01”.
If an external filter is required, the following filter should be connected to the LPF pin (A1):
LPF
R = 1 kΩ
C2 = 1 nF
C1 = 100 nF
S0514-01
Figure 56. Recommended External Loop Filter
The PLL will generate 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 requires the PFD frequency to be the
pre-defined OSTR frequency listed in Input FIFO section. This will allow the FIFO to be synced correctly by the
internal OSTR.
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 DAC3482 architecture supports this mode of operation.
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 DAC3482 this is accomplished by operating the multiple devices in Dual Sync Sources mode. In this mode
the additional OSTR signal is required by each DAC3482 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 DAC3482 FIFO so that all outputs are
phase aligned correctly.
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DACCLKP/N
OSTRP/N
D[15:0]P/N
FPGA
DAC3482 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
Delay 2
DATACLKP/N
DAC3482 DAC2
OSTRP/N
DACCLKP/N
B0454-01
Figure 57. Synchronization System 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.
LVPECL Pairs (DAC3482 1)
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.
DACCLKP/N(1)
tS(OSTR)
tH(OSTR)
tSKEW ~ 0
LVPECL Pairs (DAC3482 2)
OSTRP/N(1)
DACCLKP/N(2)
tS(OSTR)
tH(OSTR)
OSTRP/N(2)
•
•
•
•
T0526-01
Figure 58. Timing Diagram for LVPECL Synchronization Signals
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The following steps are required to ensure the devices are fully synchronized. The procedure assumes all the
DAC3482 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 DAC3482 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 “0” in register config0.
After these steps all the DAC3482 outputs will be synchronized.
MULTI-DEVICE SYNCHRONIZATION: PLL ENABLED WITH DUAL SYNC SOURCES MODE
The DAC3482 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 “1”. 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 t(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.
DACCLKP/N
SYNCP/N
D[15:0]P/N
FPGA
DAC3482 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
DAC3482 DAC2
SYNCP/N
DACCLKP/N
B0455-01
Figure 59. 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
DAC3482 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 DAC3482 in Dual Sync Sources mode
and enable SYNC to reset the PLL dividers (set pll_ndivsync_ena in register config24 to "1").
2. Reset the PLL dividers with a rising edge on SYNC.
3. Disable PLL dividers resetting.
4. Sync the clock divider and FIFO pointers.
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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 “0” in register config0.
After these steps all the DAC3482 outputs will be synchronized.
MULTI-DEVICE OPERATION: SINGLE SYNC SOURCE MODE
In Single Sync Source mode, the FIFO write and read pointers are reset from the same sync source, either
FRAME or SYNC. Although the FIFO in this mode can still absorb the data delay differences due to variations in
the digital source output paths or board level wiring it is impossible to guarantee data will be read from the FIFO
of different devices simultaneously thus preventing exact phase alignment.
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-stable situation during the pointer handoff. This meta-stable
situation can cause the outputs of the multiple devices to slip by up to 2 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.
DACCLKP/N
D[15:0]P/N
FPGA
DAC3482 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
0 to 2 DAC Clock Cycles
D[15:0]P/N
LVPECL Outputs
FRAMEP/N
Delay 2
DATACLKP/N
DAC3482 DAC2
DACCLKP/N
B0456-01
Figure 60. Multi-Device Operation in Single Sync Source Mode
FIR FILTERS
Figure 61 through Figure 64 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 65 to Figure 68 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 > 90 dB stop-band
attenuation.
The DAC3482 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 15, red line). The inverse sinc filter response (Figure 62, blue line)
has the opposite frequency response from 0 to 0.4 x Fdac, resulting in the combined response (Figure 62, green
line). Between 0 to 0.4 x fDAC, the inverse sinc filter compensates the sample-and-hold roll-off with less than 0.03
dB error.
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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 (0
dB). For example, if the signal input to FIR4 is at 0.25 x fDAC, the response of FIR4 is 0.9 dB, and the signal must
be backed off from full scale by 0.9 dB 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 4. 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
0.1
0.2
0.3
0.4
f/fIN
0.5
0.6
0.7
0.8
0.9
f/fIN
G049
Figure 61. Magnitude Spectrum for FIR0
SPACER
Figure 62. Magnitude Spectrum for FIR1
SPACER
20
20
0
0
–20
–20
–40
–40
Magnitude (dB)
Magnitude (dB)
G048
–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
1
f/fIN
G050
Figure 63. Magnitude Spectrum for FIR2
SPACER
52
1
G051
Figure 64. Magnitude Spectrum for FIR3
SPACER
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20
20
0
0
–20
–20
–40
–40
Magnitude (dB)
Magnitude (dB)
www.ti.com
–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
G052
G053
Figure 65. 2x Interpolation Composite Response
SPACER
Figure 66. 4x Interpolation Composite Response
SPACER
20
0
0
–20
–20
–40
–40
Magnitude (dB)
Magnitude (dB)
20
–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
1
2
3
f/fDATA
4
5
6
7
8
f/fDATA
G054
G055
Figure 67. 8x Interpolation Composite Response
SPACER
Figure 68. 16x Interpolation Composite Response
SPACER
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 69. Magnitude Spectrum for Inverse Sinc Filter
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Table 7. FIR Filter Coefficients
Non-Interpolating
Inverse-SINC Filter
2x 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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COMPLEX SIGNAL MIXER
The DAC3482 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 70.
16
16
16
16
I Data In
Fs/2
Mixer
16
±Fs/4
Mixer
16
16
Q Data In
CMIX<1>
sine
16
CMIX<2> CMIX<0>
I Data Out
Complex
Signal
Multiplier
16
Q Data Out
cosine
16
CMIX<3>
sine
16
cosine sine
16
16
Numerically
Controlled
Oscillator
NCO_ENA
cosine
16
Fixed Fs/8
Oscillator
B0471-01
Figure 70. Path of Complex Signal Mixer
FULL COMPLEX MIXER
The DAC3482 has a full complex mixer (FMIX) block with a Numerically Controlled Oscillators (NCO) that
enables flexible frequency placement without imposing additional limitations in the signal bandwidth. The NCO
has a 32-bit frequency registers (phaseadd(31:0)) and a 16-bit phase register (phaseoffset(15:0)) that generate
the sine and cosine terms for the complex mixing. The NCO block diagram is shown below in Figure 71.
32
16
Frequency
Register
32
32
Σ
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 71. 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 phaseadd(31:0) register 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 72) 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)
16
16
IOUT(t)
IIN(t)
16
QIN(t)
16
QOUT(t)
16
16
cosine
sine
B0472-01
Figure 72. Complex Signal Multiplier
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_offset(15:0)/216
The mixer_gain option allows the output signals of the multiplier to reduce by half (6dB). See Mixer Gain Section
for detail.
COARSE COMPLEX MIXER
In addition to the full complex mixer, the DAC3482 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 8 shows
the algorithm used for those mixer blocks.
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Table 8. Fs/2, Fs/4, and –Fs/4 Mixing Sequence
MODE
MIXING SEQUENCE
Iout = {+I1, +I2, +I3, +I4…}
Normal (mixer bypassed)
Qout = {+Q1, +Q2, +Q3, +Q4…}
Iout = {+I1, -I2, +I3, -I4…}
fs/2
Qout = {+Q1, -Q2, +Q3, -Q4…}
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 9. The mixer_gain option allows the output signals of the multiplier to reduce by half (6dB). See Mixer Gain
section for detail.
Table 9. 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
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 73. 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.
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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 3 dB to compensate.
REAL CHANNEL UPCONVERSION
The mixer in the DAC3482 treats the I and Q 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 8 for details.
QUADRATURE MODULATION CORRECTION (QMC)
GAIN AND PHASE CORRECTION
The DAC3482 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 74. The QMC block
contains 3 programmable parameters.
Register qmc_gain(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_phase(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 +3.75 to –3.75 degrees in 1024 steps.
LO feed-through can be minimized by adjusting the DAC offset feature described below.
qmc_gain[10:0]
11
16
Σ
I Data In
16
I Data Out
12
qmc_phase[11:0]
16
16
Q Data In
Q Data Out
11
qmc_gain[10:0]
B0164-02
Figure 74. QMC Block Diagram
OFFSET CORRECTION
Registers qmc_offsetI(12:0) and qmc_offsetQ(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_offsetI
{–4096, –4095, ..., 4095}
13
16
I Data In
16
Q Data In
16
Σ
I Data Out
16
Σ
Q Data Out
13
qmc_offsetQ
{–4096, –4095, ..., 4095}
B0165-02
Figure 75. Digital Offset Block Diagram
GROUP DELAY CORRECTION
A complex transmitter system typically is consisted of a DAC, 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 DAC3482 has group delay
correction block for each DAC channel. Each DAC channel can adjust its delay through grp_delayI(7:0) and
grp_delayq(7:0) in register config46 and config47, respectively. The maximum delay ranges from 30ps to 100ps
and is dependent on DAC sample clock. Contact TI for specific application information. The group delay
correction, along with gain/phase correction, can be useful for correcting imbalances in wide-band transmitter
system.
TEMPERATURE SENSOR
The DAC3482 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.
The sampling is controlled by the serial interface signals SDENB and SCLK. If the temperature sensor is enabled
(tsense_sleep = 0 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.
DATA PATTERN CHECKER
The DAC3482 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.
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The first word in the test frame is determined by a rising edge transition in FRAME or SYNC, depending on the
syncsel_fifoin(3:0) 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 0. 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 76. 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 “1” 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 “1” to indicate an error in bit 0 location. The alarm_from_iotest will also be set to
“1” to report the data transfer error. The user can then narrow down the error from the alarm_from_iotest bit
location information and implement the fix accordingly.
The alarms can be cleared by writing 0x0000 to iotest_results(15:0) and “0” 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 “1” if the errors remain.
Note that unless the unused data pins in byte-wide input format are forced to a known value the data pattern
checker is only available for the word-wide input data format. In byte-wide input format, the first 8-bits of the
iotest_pattern[0:7] in registers config37 through config44 will either need to be 0s or 1s for valid data pattern
checking.
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.
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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
Data
Format
edge needed
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
•
•
•
•
•
•
alarm_from_iotest
iotest_results[0]
All Bits
Results
Bit 0
Results
Go back to 0 after cycle or new
rising edge on FRAME or SYNC
B0457-01
Figure 77. DAC3482 Pattern Check Block Diagram
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PARITY CHECK TEST
The DAC3482 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 logic value of “1”) is even or odd. This simple scheme is used to detect data transfer errors. Parity
testing is implemented in the DAC3482 in two ways: word-by-word parity and block parity.
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 “1” 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.
Note that unless the unused data pins in byte-wide input format are forced to a known value the word-by-word
parity is only available for the word-wide input data format.
Figure 78 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 78. DAC3482 Word-by-Word Parity Check
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 “1”. The main advantage of the block parity mode
is that there is no need for an additional parity LVDS input.
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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 I and 16-bits
Q). In addition since FRAME is used in byte-wide input data mode to establish the frame boundary, the parity
block must be aligned with the data frame boundaries.
I0
[15:0]
D[15:0]P/N
Q0
[15:0]
I1
[15:0]
Q1
[15:0]
D[15:0]P/N
DATACLKP/N
(DDR)
•••
•••
High = Odd Parity
Low = Even Parity
FRAMEP/N
Ix
[15:0]
Qx
[15:0]
Iy
[15:0]
Qy
[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
T0527-01
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 79. DAC3482 Block Parity Check (Example shown with Word-Wide Mode)
DAC3482 ALARM MONITORING
The DAC3482 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 point 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.
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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).
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.
POWER-UP SEQUENCE
The following startup sequence is recommended to power-up the DAC3482:
1. Set TXENABLE low
2. Supply all 1.2V voltages (DACVDD, DIGVDD, CLKVDD and VFUSE) and all 3.3V voltages (AVDD, IOVDD,
and PLLAVDD). The 1.2V and 3.3V 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 config1, bit <8> = "0" and config16, bit <13:12> = "11".
7. Program fuse_sleep (config 27, Bit <11> ) to put internal fuses to sleep.
8. FIFO configuration needed for synchronization:
(a) Program syncsel_fifoin(3:0) (config32, bit<15:12>) to select the FIFO input pointer sync source.
(b) Program syncsel_fifoout(3:0) (config32, bit<11:8>) to select the FIFO output pointer sync source.
(c) Program syncsel_dataformatter(1:0) (config32, bit<3:2>) to select the FIFO Data Formatter sync source.
9. 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 "1" to enable clock divider sync.
(c) For multi-DAC synchronization in PLL mode, program pll_ndivsync_ena (config24, bit<11>) to “1” to
synchronize the PLL N-divider.
10. 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
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.
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(c) For multi-DAC synchronization in PLL mode, the LVDS SYNCP/N signal is used to sync the PLL
N-divider 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.
11. 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 DAC3482 initialization and before the data transmission by
setting clkdiv_sync_ena (config0, bit 2) to “0”. This is to prevent accidental syncing of the clock divider or
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 “0000” after the FIFO input and output pointers are
initialized. Also Disable the FIFO data formatter by setting syncsel_dataformatter(1:0) to “10” or “11”. 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 "0".
12. Enable transmit of data by asserting the TXENABLE pin or set sif_txenable to “1”.
13. 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 8 through 12.
Program the FIFO configuration and clock divider configuration per steps 8 and 9 appropriately to accept the
new sync pulse or pulses for the synchronization.
EXAMPLE START-UP ROUTINE
DEVICE CONFIGURATION
fDATA = 614.4MSPS, 16-bit word wide interface
Interpolation = 2x
Input data = baseband data
fOUT = 122.88MHz
PLL = Enabled
Full Mixer = Enabled
Dual Sync Sources Mode
PLL CONFIGURATION
fREFCLK = 614.4MHz at the DACCLKP/N LVPECL pins
fDACCLK = fDATA x Interpolation = 1228.8MHz
fVCO = 3 x fDACCLK = 3686.4MHz (keep fVCO between 3.3GHz to 4GHz)
PFD = fOSTR = 38.4MHz
N = 16, M = 32, P = 3, single charge pump
pll_vco(5:0) = “100100” (36)
NCO CONFIGURATION
fNCO = 122.88MHz
fNCO_CLK = 1228.8MHz
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freq = fCNO x 2^32 / 1228.8 = 429496730 = 0x1999999A
phaseaddAB(31:0) or phaseaddCD(31:0) = 0x1999999A
NCO SYNC = sif_sync
EXAMPLE START-UP SEQUENCE
Table 10. Example Start-Up Sequence Description
66
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
0xA19E
QMC offset and correction enabled, 2x int, FIFO enabled, Alarm enabled,
clock divider sync enabled, inverse sinc filter enabled.
6
Write
0x01
0x040E
Single parity enabled, FIFO alarms enabled (2 away, 1 away, and collision).
Note: bit8 = ‘0’
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 1.28kohm 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 I QMC offset value. (Causes Auto-Sync for
QMC Offset Block)
11
Write
0x09
N/A
Program the desired FIFO offset value and channel Q QMC offset value.
12
Write
0x0C
N/A
Program the desired channel I QMC gain value.
13
Write
0x0D
N/A
Coarse mixer mode not used. Program the desired channel Q QMC gain
value.
14
Write
0x10
N/A
Program the desired channel IQ QMC phase value. (Causes Auto-Sync
QMC Correction Block) Note : bit13 and bit12 = ‘1’
15
Write
0x12
N/A
Program the desired channel IQ NCO phase offset value. (Causes
Auto-Sync for Channel IQ NCO Mixer)
16
Write
0x14
0x999A
Program the desired channel IQ NCO frequency value
17
Write
0x15
0x1999
Program the desired channel IQ NCO frequency value
18
Write
0x18
0x2C58
PLL enabled, PLL N-dividers sync enabled, single charge pump, prescaler =
3.
19
Write
0x19
0x20F4
M = 32, N = 16, PLL VCO bias tune = “01”
20
Write
0x1A
0x9000
PLL VCO coarse tune = 36
21
Write
0x1B
0x0800
Internal reference
22
Write
0x1E
0x9191
QMC offset IQ and QMC correction IQ can be synced by sif_sync or
auto-sync from register write
23
Write
0x1F
0x4140
Mixer IQ values synced by SYNCP/N. NCO accumulator synced by
SYNCP/N. FIFO data formatter synced by FRAMEP/N.
24
Write
0x20
0x2400
FIFO Input Pointer Sync Source = FRAME
FIFO Output Pointer Sync Source = OSTR (from PLL N-divider output)
Clock Divider Sync Source = OSTR
25
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 N-dividers.
26
Read
0x18
N/A
Read back pll_lfvolt(2:0). If the value is not optimal, adjust pll_vco(5:0) in
0x1A.
27
Write
0x05
0x0000
28
Read
0x05
N/A
Clear all alarms in 0x05.
Read back all alarms in 0x05. Check for PLL lock, FIFO collision,
DACCLK-gone, DATACLK-gone, etc. Fix the error appropriately. Repeat
step 26 and 27 as necessary.
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Table 10. Example Start-Up Sequence Description (continued)
STEP
READ/WRITE
ADDRESS
VALUE
DESCRIPTION
29
Write
0x1F
0x4142
Sync all the QMC blocks using sif_sync. These blocks can also be synced
via auto-sync through appropriate register writes.
30
Write
0x00
0xA19A
Disable clock divider sync.
31
Write
0x1F
0x4148
Disable FIFO data formatter sync. Set sif_sync to “0” for the next sif_sync
event.
32
Write
0x20
0x0000
Disable FIFO input and output pointer sync.
33
Write
0x18
0x2458
Disable PLL N-dividers sync.
34
N/A
N/A
N/A
Set TXENABLE high. Enable data transmission.
LVPECL INPUTS
Figure 80 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
250 Ω
Internal
Digital In
SLEEP
GND
S0515-01
Figure 80. DACCLKP/N and OSTRP/N Equivalent Input Circuit
Figure 81 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
Figure 81. Preferred Clock Input Configuration with a Differential ECL/PECL Clock Source
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 82. Figure 83 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 82. D[15:0]P/N, DATACLKP/N, FRAMEP/N, SYNCP/N and PARITYP/N LVDS Input Configuration
Example
DAC3482
VA, B
VCOM = (VA + VB)/2
VA
1.4 V
VB
1V
LVDS
Receiver
100 Ω
400 mV
VA, B
VA
0V
–400 mV
VB
GND
Logical Bit
Equivalent
1
0
B0459-01
Figure 83. LVDS Data Input Levels
68
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Table 11. Example LVDS Data Input Levels
Applied Voltages
Resulting Differential
Voltage
Resulting Common-Mode
Voltage
VA,B
VCOM
1.2 V
VA
VB
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
Logical Bit Binary
Equivalent
1
0
1.0 V
1
0
CMOS DIGITAL INPUTS
Figure 84 shows a schematic of the equivalent CMOS digital inputs of the DAC3482. SDIO, SCLK, SLEEP and
TXENABLE have pull-down resistors while SDENB and RESETB have pull-up resistors internal to the DAC3482.
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
SDENB
RESETB
GND
400 Ω
Internal
Digital In
GND
S0027-03
Figure 84. CMOS Digital Equivalent Input
REFERENCE OPERATION
The DAC3482 uses a bandgap reference and control amplifier for biasing the full-scale output current. The
full-scale 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 DAC3482 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
1.2V. This reference is active when extref_ena = ‘0’ 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, programming
coarse_dac(3:0), or changing the externally applied reference voltage.
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NOTE
With internal reference, the minimum Rbias resistor value is 1.28kΩ. Resistor value below
1.28kΩ is not recommended since it will program the full-scale current to go above 30mA
and potentially damages the device.
DAC TRANSFER FUNCTION
The CMOS DAC’s 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.
ANALOG CURRENT OUTPUTS
The DAC3482 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.
70
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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
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Product Folder Link(s): DAC3482
71
DAC3482
SLAS748A – MARCH 2011 – REVISED JUNE 2011
www.ti.com
REVISION HISTORY
Changes from Original (March 2011) to Revision A
•
72
Page
Changed from PRODUCT PREVIEW to PRODUCTION DATA ........................................................................................... 1
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Product Folder Link(s): DAC3482
PACKAGE OPTION ADDENDUM
www.ti.com
27-Jun-2011
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package
Drawing
Pins
Package Qty
Eco Plan
(2)
Lead/
Ball Finish
MSL Peak Temp
(3)
(Requires Login)
DAC3482IRKDR
ACTIVE
WQFN
RKD
88
2000
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
DAC3482IRKDT
ACTIVE
WQFN
RKD
88
250
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
PDAC3482IRKDT
PREVIEW
WQFN
RKD
88
TBD
Call TI
Samples
Call TI
(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.
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 1
PACKAGE MATERIALS INFORMATION
www.ti.com
27-Jun-2011
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
DAC3482IRKDR
WQFN
RKD
88
2000
330.0
16.4
9.3
9.3
1.5
12.0
16.0
Q2
DAC3482IRKDT
WQFN
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
27-Jun-2011
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
DAC3482IRKDR
WQFN
RKD
88
2000
333.2
345.9
28.6
DAC3482IRKDT
WQFN
RKD
88
250
333.2
345.9
28.6
Pack Materials-Page 2
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