AD AD9253BCPZ-80

FUNCTIONAL BLOCK DIAGRAM
AVDD
GENERAL DESCRIPTION
The AD9253 is a quad, 14-bit, 80 MSPS/105 MSPS/125 MSPS
analog-to-digital converter (ADC) with an on-chip sampleand-hold circuit designed for low cost, low power, small size,
and ease of use. The product operates at a conversion rate of
up to 125 MSPS and is optimized for outstanding dynamic
performance and low power in applications where a small
package size is critical.
The ADC requires a single 1.8 V power supply and LVPECL-/
CMOS-/LVDS-compatible sample rate clock for full performance
operation. No external reference or driver components are
required for many applications.
The ADC automatically multiplies the sample rate clock for the
appropriate LVDS serial data rate. A data clock output (DCO) for
capturing data on the output and a frame clock output (FCO)
for signaling a new output byte are provided. Individual-channel
power-down is supported and typically consumes less than 2 mW
when all channels are disabled. The ADC contains several features
designed to maximize flexibility and minimize system cost, such
DIGITAL
SERIALIZER
PIPELINE
ADC
SENSE
PIPELINE
ADC
VIN+D
VIN–D
PIPELINE
ADC
DIGITAL
SERIALIZER
14
DIGITAL
SERIALIZER
CLK–
CLK+
CLOCK
MANAGEMENT
SYNC
SERIAL PORT
INTERFACE
SCLK/DTP
VCM
D0+B
D0–B
SERIAL
LVDS
SERIAL
LVDS
D1+B
D1–B
FCO+
FCO–
D0+C
D0–C
D1+C
D1–C
SERIAL
LVDS
D0+D
D0–D
SERIAL
LVDS
D1+D
D1–D
DCO+
DCO–
SERIAL
LVDS
14
VIN+C
VIN–C
SERIAL
LVDS
AD9253
1V
REF
SELECT
SERIAL
LVDS
D0+A
D0–A
D1+A
D1–A
SERIAL
LVDS
14
VIN–B
RBIAS
VREF
AGND
DRVDD
DIGITAL
SERIALIZER
PIPELINE
ADC
VIN+B
APPLICATIONS
Medical ultrasound
High speed imaging
Quadrature radio receivers
Diversity radio receivers
Test equipment
PDWN
14
VIN+A
VIN–A
CSB
1.8 V supply operation
Low power: 110 mW per channel at 125 MSPS with scalable
power options
SNR = 74 dB (to Nyquist)
SFDR = 90 dBc (to Nyquist)
DNL = ±0.75 LSB (typical); INL = ±2.0 LSB (typical)
Serial LVDS (ANSI-644, default) and low power, reduced
signal option (similar to IEEE 1596.3)
650 MHz full power analog bandwidth
2 V p-p input voltage range
Serial port control
Full chip and individual channel power-down modes
Flexible bit orientation
Built-in and custom digital test pattern generation
Multichip sync and clock divider
Programmable output clock and data alignment
Programmable output resolution
Standby mode
10065-001
FEATURES
SDIO/OLM
Data Sheet
Quad, 14-Bit, 80 MSPS/105 MSPS/125 MSPS
Serial LVDS 1.8 V Analog-to-Digital Converter
AD9253
Figure 1.
as programmable output clock and data alignment and digital
test pattern generation. The available digital test patterns
include built-in deterministic and pseudorandom patterns, along
with custom user-defined test patterns entered via the serial port
interface (SPI).
The AD9253 is available in a RoHS-compliant, 48-lead LFCSP.
It is specified over the industrial temperature range of −40°C to
+85°C. This product is protected by a U.S. patent.
PRODUCT HIGHLIGHTS
1.
2.
3.
4.
5.
Small Footprint. Four ADCs are contained in a small, spacesaving package.
Low power of 110 mW/channel at 125 MSPS with scalable
power options.
Pin compatible to the AD9633 12-bit quad ADC.
Ease of Use. A data clock output (DCO) operates at
frequencies of up to 500 MHz and supports double data
rate (DDR) operation.
User Flexibility. The SPI control offers a wide range of
flexible features to meet specific system requirements.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2011 Analog Devices, Inc. All rights reserved.
AD9253
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1 Clock Input Considerations...................................................... 24 Applications....................................................................................... 1 Power Dissipation and Power-Down Mode ........................... 26 General Description ......................................................................... 1 Digital Outputs and Timing ..................................................... 27 Functional Block Diagram .............................................................. 1 Output Test Modes..................................................................... 30 Product Highlights ........................................................................... 1 Serial Port Interface (SPI).............................................................. 31 Revision History ............................................................................... 2 Configuration Using the SPI..................................................... 31 Specifications..................................................................................... 3 Hardware Interface..................................................................... 32 DC Specifications ......................................................................... 3 Configuration Without the SPI ................................................ 32 AC Specifications.......................................................................... 4 SPI Accessible Features.............................................................. 32 Digital Specifications ................................................................... 5 Memory Map .................................................................................. 33 Switching Specifications .............................................................. 6 Reading the Memory Map Register Table............................... 33 Timing Specifications .................................................................. 6 Memory Map Register Table..................................................... 34 Absolute Maximum Ratings.......................................................... 11 Memory Map Register Descriptions........................................ 37 Thermal Resistance .................................................................... 11 Applications Information .............................................................. 39 ESD Caution................................................................................ 11 Design Guidelines ...................................................................... 39 Pin Configuration and Function Descriptions........................... 12 Power and Ground Recommendations ................................... 39 Typical Performance Characteristics ........................................... 14 Exposed Pad Thermal Heat Slug Recommendations............ 39 AD9253-80 .................................................................................. 14 VCM............................................................................................. 39 AD9253-105 ................................................................................ 16 Reference Decoupling................................................................ 39 AD9253-125 ................................................................................ 18 SPI Port ........................................................................................ 39 Equivalent Circuits ......................................................................... 21 Crosstalk Performance .............................................................. 39 Theory of Operation ...................................................................... 22 Outline Dimensions ....................................................................... 40 Analog Input Considerations.................................................... 22 Ordering Guide .......................................................................... 40 Voltage Reference ....................................................................... 23 REVISION HISTORY
10/11—Revision 0: Initial Version
Rev. 0 | Page 2 of 40
Data Sheet
AD9253
SPECIFICATIONS
DC SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, 2 V p-p differential input, 1.0 V internal reference, AIN = −1.0 dBFS, unless otherwise noted.
Table 1.
Parameter 1
RESOLUTION
ACCURACY
No Missing Codes
Offset Error
Offset Matching
Gain Error
Gain Matching
Differential Nonlinearity (DNL)
Integral Nonlinearity (INL)
TEMPERATURE DRIFT
Offset Error
INTERNAL VOLTAGE REFERENCE
Output Voltage (1 V Mode)
Load Regulation at 1.0 mA (VREF = 1 V)
Input Resistance
INPUT-REFERRED NOISE
VREF = 1.0 V
ANALOG INPUTS
Differential Input Voltage (VREF = 1 V)
Common-Mode Voltage
Differential Input Resistance
Differential Input Capacitance
POWER SUPPLY
AVDD
DRVDD
IAVDD 2
IDRVDD (ANSI-644 Mode)2
IDRVDD (Reduced Range Mode)2
TOTAL POWER CONSUMPTION
DC Input
Sine Wave Input (Four Channels Including
Output Drivers ANSI-644 Mode)
Sine Wave Input (Four Channels Including
Output Drivers Reduced Range Mode)
Power-Down
Standby 3
Temp
AD9253-80
Min Typ Max
14
AD9253-105
Min Typ
Max
14
AD9253-125
Min Typ
Max
14
Unit
Bits
Full
Full
Full
Full
Full
Full
25°C
Full
25°C
Guaranteed
−0.7 −0.3 +0.1
−0.6 +0.2 +0.6
−10 −5
0
1
1.6
−1
+1.6
±0.8
−4.0
+4.0
±1.5
Guaranteed
−0.7 −0.3
+0.1
−0.6 +0.2
+0.6
−10 −5
0
1
1.6
−0.8
+1.5
±0.75
−4.0
4.0
±2.0
Guaranteed
−0.7 −0.3
+0.1
−0.6 +0.2
+0.6
−10 −5
0
1.1
1.6
−0.8
+1.5
±0.75
−4.0
+4.0
±2.0
% FSR
% FSR
% FSR
% FSR
LSB
LSB
LSB
LSB
Full
Full
Full
Full
±2
0.98
1.0
2
7.5
±2
1.02
0.98
1.0
2
7.5
±2
1.02
0.98
1.0
2
7.5
ppm/°C
1.02
V
mV
kΩ
25°C
0.94
0.94
0.94
LSB rms
Full
Full
2
0.9
5.2
3.5
2
0.9
5.2
3.5
2
0.9
5.2
3.5
V p-p
V
kΩ
pF
Full
Full
Full
Full
Full
25°C
1.7
1.7
1.8
1.8
131
63
42
1.9
1.9
144
81
1.7
1.7
1.8
1.8
158
67
48
1.7
1.7
1.8
1.8
183
71
53
V
V
mA
mA
mA
326
349
25°C
311
371
425
mW
Full
Full
2
178
2
209
2
236
mW
mW
1
481
423
457
1.9
1.9
200
100
Full
Full
405
375
405
1.9
1.9
172
95
540
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and for details on how these tests were completed.
Measured with a low input frequency, full-scale sine wave on all four channels.
3
Can be controlled via the SPI.
2
Rev. 0 | Page 3 of 40
mW
mW
AD9253
Data Sheet
AC SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, 2 V p-p differential input, 1.0 V internal reference, AIN = −1.0 dBFS, unless otherwise noted.
Table 2.
Parameter 1
SIGNAL-TO-NOISE RATIO (SNR)
fIN = 9.7 MHz
fIN = 30.5 MHz
fIN = 70 MHz
fIN = 140 MHz
fIN = 200 MHz
SIGNAL-TO-NOISE-AND-DISTORTION RATIO (SINAD)
fIN = 9.7 MHz
fIN = 30.5 MHz
fIN = 70 MHz
fIN = 140 MHz
fIN = 200 MHz
EFFECTIVE NUMBER OF BITS (ENOB)
fIN = 9.7 MHz
fIN = 30.5 MHz
fIN = 70 MHz
fIN = 140 MHz
fIN = 200 MHz
SPURIOUS-FREE DYNAMIC RANGE (SFDR)
fIN = 9.7 MHz
fIN = 30.5 MHz
fIN = 70 MHz
fIN = 140 MHz
fIN = 200 MHz
WORST HARMONIC (SECOND OR THIRD)
fIN = 9.7 MHz
fIN = 30.5 MHz
fIN = 70 MHz
fIN = 140 MHz
fIN = 200 MHz
WORST OTHER HARMONIC (EXCLUDING SECOND OR THIRD)
fIN = 9.7 MHz
fIN = 30.5 MHz
fIN = 70 MHz
fIN = 140 MHz
fIN = 200 MHz
TWO-TONE INTERMODULATION DISTORTION (IMD)—AIN1 AND
AIN2 = −7.0 dBFS
fIN1 = 70.5 MHz, fIN2 = 72.5 MHz
CROSSTALK 2
CROSSTALK (OVERRANGE CONDITION) 3
POWER SUPPLY REJECTION RATIO (PSRR)1, 4
AVDD
DRVDD
ANALOG INPUT BANDWIDTH, FULL POWER
Temp
25°C
25°C
Full
25°C
25°C
25°C
25°C
Full
25°C
25°C
AD9253-80
Min Typ
Max
AD9253-105
Min Typ Max
AD9253-125
Min Typ
Max
Unit
72.2
75.4
74.9
74.7
72.3
70.7
72.2
75.1
75.0
74.4
73.1
71.2
73
75.3
75.2
74.2
72.2
70.7
dBFS
dBFS
dBFS
dBFS
dBFS
70.8
75.3
74.8
74.6
72.1
70.5
69.8
75.0
74.9
74.2
72.8
70.8
71.6
75.2
75.1
74.1
71.9
70.4
dBFS
dBFS
dBFS
dBFS
dBFS
25°C
25°C
Full
25°C
25°C
12.2
12.1
11.9
11.6
11.5
12.1
12.1
12.0
11.8
11.5
12.2
12.1
12.0
11.6
11.4
Bits
Bits
Bits
Bits
Bits
25°C
25°C
Full
25°C
25°C
98
93
94
85
84
98
92
89
85
82
98
92
90
85
83
dBc
dBc
dBc
dBc
dBc
−75
−98
−92
−90
−85
−83
−77
dBc
dBc
dBc
dBc
dBc
−77
−101
−100
−95
−96
−92
−84
dBFS
dBFS
dBFS
dBFS
dBFS
77
75
25°C
25°C
Full
25°C
25°C
−98
−93
−94
−85
−84
25°C
25°C
Full
25°C
25°C
−100
−99
−98
−98
−95
25°C
Full
25°C
90
−95
−89
88
−95
−89
86
−95
−89
dBc
dB
dB
25°C
25°C
25°C
48
75
650
48
75
650
48
75
650
dB
dB
MHz
1
−77
−98
−92
−89
−85
−82
−77
−99
−99
−95
−98
−92
77
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and for details on how these tests were completed.
Crosstalk is measured at 70 MHz with −1.0 dBFS analog input on one channel and no input on the adjacent channel.
3
Overrange condition is specified with 3 dB of the full-scale input range.
4
PSRR is measured by injecting a sinusoidal signal at 10 MHz to the power supply pin and measuring the output spur on the FFT. PSRR is calculated as the ratio of the
amplitudes of the spur voltage over the pin voltage, expressed in decibels.
2
Rev. 0 | Page 4 of 40
Data Sheet
AD9253
DIGITAL SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, 2 V p-p differential input, 1.0 V internal reference, AIN = −1.0 dBFS, unless otherwise noted.
Table 3.
Parameter 1
CLOCK INPUTS (CLK+, CLK−)
Logic Compliance
Differential Input Voltage 2
Input Voltage Range
Input Common-Mode Voltage
Input Resistance (Differential)
Input Capacitance
LOGIC INPUTS (PDWN, SYNC, SCLK)
Logic 1 Voltage
Logic 0 Voltage
Input Resistance
Input Capacitance
LOGIC INPUT (CSB)
Logic 1 Voltage
Logic 0 Voltage
Input Resistance
Input Capacitance
LOGIC INPUT (SDIO)
Logic 1 Voltage
Logic 0 Voltage
Input Resistance
Input Capacitance
LOGIC OUTPUT (SDIO) 3
Logic 1 Voltage (IOH = 800 μA)
Logic 0 Voltage (IOL = 50 μA)
DIGITAL OUTPUTS (D0±x, D1±x), ANSI-644
Logic Compliance
Differential Output Voltage (VOD)
Output Offset Voltage (VOS)
Output Coding (Default)
DIGITAL OUTPUTS (D0±x, D1±x), LOW POWER,
REDUCED SIGNAL OPTION
Logic Compliance
Differential Output Voltage (VOD)
Output Offset Voltage (VOS)
Output Coding (Default)
1
2
3
Temp
Min
Full
Full
Full
25°C
25°C
0.2
AGND − 0.2
Full
Full
25°C
25°C
1.2
0
Full
Full
25°C
25°C
1.2
0
Full
Full
25°C
25°C
1.2
0
Typ
Max
Unit
3.6
AVDD + 0.2
V p-p
V
V
kΩ
pF
AVDD + 0.2
0.8
V
V
kΩ
pF
AVDD + 0.2
0.8
V
V
kΩ
pF
AVDD + 0.2
0.8
V
V
kΩ
pF
CMOS/LVDS/LVPECL
0.9
15
4
30
2
26
2
26
5
Full
Full
1.79
0.05
V
V
Full
Full
290
1.15
LVDS
345
400
1.25
1.35
Twos complement
mV
V
Full
Full
160
1.15
LVDS
200
230
1.25
1.35
Twos complement
mV
V
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and for details on how these tests were completed.
This is specified for LVDS and LVPECL only.
This is specified for 13 SDIO/OLM pins sharing the same connection.
Rev. 0 | Page 5 of 40
AD9253
Data Sheet
SWITCHING SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, 2 V p-p differential input, 1.0 V internal reference, AIN = −1.0 dBFS, unless otherwise noted.
Table 4.
Parameter1, 2
CLOCK3
Input Clock Rate
Conversion Rate
Clock Pulse Width High (tEH)
Clock Pulse Width Low (tEL)
OUTPUT PARAMETERS3
Propagation Delay (tPD)
Rise Time (tR) (20% to 80%)
Fall Time (tF) (20% to 80%)
FCO Propagation Delay (tFCO)
DCO Propagation Delay (tCPD)4
DCO to Data Delay (tDATA)4
DCO to FCO Delay (tFRAME)4
Lane Delay (tLD)
Data to Data Skew (tDATA-MAX − tDATA-MIN)
Wake-Up Time (Standby)
Wake-Up Time (Power-Down)5
Pipeline Latency
APERTURE
Aperture Delay (tA)
Aperture Uncertainty (Jitter, tJ)
Out-of-Range Recovery Time
Temp
Min
Full
Full
Full
Full
10
10
Full
Full
Full
Full
Full
Full
Full
Typ
Max
Unit
1000
80/105/125
MHz
MSPS
ns
ns
6.25/4.76/4.00
6.25/4.76/4.00
Full
25°C
25°C
Full
2.3
300
300
2.3
tFCO + (tSAMPLE/16)
(tSAMPLE/16)
(tSAMPLE/16)
90
±50
250
375
16
25°C
25°C
25°C
1
135
1
1.5
(tSAMPLE/16) − 300
(tSAMPLE/16) − 300
ns
ps
ps
ns
ns
ps
ps
ps
ps
ns
μs
3.1
(tSAMPLE/16) + 300
(tSAMPLE/16) + 300
±200
Clock cycles
ns
fs rms
Clock cycles
1
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and for details on how these tests were completed.
Measured on standard FR-4 material.
3
Can be adjusted via the SPI. The conversion rate is the clock rate after the divider.
4
tSAMPLE/16 is based on the number of bits in two LVDS data lanes. tSAMPLE = 1/fS.
5
Wake-up time is defined as the time required to return to normal operation from power-down mode.
2
TIMING SPECIFICATIONS
Table 5.
Parameter
SYNC TIMING REQUIREMENTS
tSSYNC
tHSYNC
SPI TIMING REQUIREMENTS
tDS
tDH
tCLK
tS
tH
tHIGH
tLOW
tEN_SDIO
tDIS_SDIO
Description
Limit
Unit
SYNC to rising edge of CLK+ setup time
SYNC to rising edge of CLK+ hold time
See Figure 74
Setup time between the data and the rising edge of SCLK
Hold time between the data and the rising edge of SCLK
Period of the SCLK
Setup time between CSB and SCLK
Hold time between CSB and SCLK
SCLK pulse width high
SCLK pulse width low
Time required for the SDIO pin to switch from an input to an output relative to the
SCLK falling edge (not shown in Figure 74)
Time required for the SDIO pin to switch from an output to an input relative to the
SCLK rising edge (not shown in Figure 74)
0.24
0.40
ns typ
ns typ
2
2
40
2
2
10
10
10
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
10
ns min
Rev. 0 | Page 6 of 40
Data Sheet
AD9253
Timing Diagrams
Refer to the Memory Map Register Descriptions section and Table 21 for SPI register settings.
N–1
VIN±x
N
tA
CLK–
tEH
N+1
tEL
CLK+
DCO–
tCPD
DDR
DCO+
DCO–
SDR
DCO+
FCO–
FCO+
D0–A
BITWISE
MODE
D0+A
tFCO
tFRAME
tPD
tDATA
D12
N – 17
D10
N – 17
D08
N – 17
D06
N – 17
D04
N – 17
D02
N – 17
LSB
N – 17
0
N – 17
MSB
N – 17
D11
N – 17
D09
N – 17
D07
N – 17
D05
N – 17
D03
N – 17
D01
N – 17
0
N – 17
D10
N – 16
D08
N – 16
D06
N – 16
D04
N – 16
D02
N – 16
LSB
N – 16
0
N – 16
MSB
N – 16
D11
N – 16
D09
N – 16
D07
N – 16
D05
N – 16
D03
N – 16
D01
N – 16
0
N – 16
D05
N – 17
D04
N – 17
D03
N – 17
D02
N – 17
D01
N – 17
LSB
N – 17
0
N – 17
0
N – 17
D05
N – 16
D04
N – 16
D03
N – 16
D02
N – 16
D01
N – 16
LSB
N – 16
0
N – 16
0
N – 16
MSB
N – 17
D12
N – 17
D11
N – 17
D10
N – 17
D09
N – 17
D08
N – 17
D07
N – 17
D06
N – 17
MSB
N – 16
D12
N – 16
D11
N – 16
D10
N – 16
D09
N – 16
D08
N – 16
D07
N – 16
D06
N – 16
tLD
D1–A
D1+A
D12
N – 16
FCO–
D0–A
D0+A
D1–A
D1+A
Figure 2. 16-Bit DDR/SDR, Two-Lane, 1× Frame Mode (Default)
Rev. 0 | Page 7 of 40
10065-003
FCO+
BYTEWISE
MODE
AD9253
Data Sheet
N–1
VIN±x
N+1
tA
N
tEH
CLK–
CLK+
tEL
tCPD
DCO–
DDR
DCO+
DCO–
SDR
DCO+
FCO+
BITWISE
MODE
tFRAME
tFCO
FCO–
tDATA
tPD
D0–A
D0+A
D10
N – 17
D08
N – 17
D06
N – 17
D04
N – 17
D02
N – 17
LSB
N – 17
D10
N – 16
D08
N – 16
D06
N – 16
MSB
N – 17
D09
N – 17
D07
N – 17
D05
N – 17
D03
N – 17
D01
N – 17
MSB
N – 16
D09
N – 16
D07
N – 16
D05
N – 17
D04
N – 17
D03
N – 17
D02
N – 17
D01
N – 17
LSB
N – 17
D05
N – 16
D04
N – 16
MSB
N – 17
D10
N – 17
D09
N – 17
D08
N – 17
D07
N – 17
D06
N – 17
MSB
N – 16
D10
N – 16
D04
N – 16
D02
N – 16
LSB
N – 16
D05
N – 16
D03
N – 16
D01
N – 16
D03
N – 16
D02
N – 16
D01
N – 16
LSB
N – 16
D09
N – 16
D08
N – 16
D07
N – 16
D06
N – 16
tLD
D1–A
D1+A
FCO–
FCO+
BYTEWISE
MODE
D0–A
D0+A
10065-004
D1–A
D1+A
Figure 3. 12-Bit DDR/SDR, Two-Lane, 1× Frame Mode
N–1
VIN±x
N
tA
CLK–
tEH
N+1
tEL
CLK+
DCO–
tCPD
DDR
DCO+
DCO–
SDR
DCO+
FCO–
FCO+
D0–A
BITWISE
MODE
D0+A
tFCO
tFRAME
tPD
tDATA
D12
N – 17
D10
N – 17
D08
N – 17
D06
N – 17
D04
N – 17
D02
N – 17
LSB
N – 17
0
N – 17
MSB
N – 17
D11
N – 17
D09
N – 17
D07
N – 17
D05
N – 17
D03
N – 17
D01
N – 17
0
N – 17
D10
N – 16
D08
N – 16
D06
N – 16
D04
N – 16
D02
N – 16
LSB
N – 16
0
N – 16
MSB
N – 16
D11
N – 16
D09
N – 16
D07
N – 16
D05
N – 16
D03
N – 16
D01
N – 16
0
N – 16
D05
N – 17
D04
N – 17
D03
N – 17
D02
N – 17
D01
N – 17
LSB
N – 17
0
N – 17
0
N – 17
D05
N – 16
D04
N – 16
D03
N – 16
D02
N – 16
D01
N – 16
LSB
N – 16
0
N – 16
0
N – 16
MSB
N – 17
D12
N – 17
D11
N – 17
D10
N – 17
D09
N – 17
D08
N – 17
D07
N – 17
D06
N – 17
MSB
N – 16
D12
N – 16
D11
N – 16
D10
N – 16
D09
N – 16
D08
N – 16
D07
N – 16
D06
N – 16
tLD
D1–A
D1+A
D12
N – 16
FCO–
D0–A
D0+A
D1–A
D1+A
Figure 4. 16-Bit DDR/SDR, Two-Lane, 2× Frame Mode
Rev. 0 | Page 8 of 40
10065-005
FCO+
BYTEWISE
MODE
Data Sheet
AD9253
N–1
VIN±x
N+1
tA
N
tEH
CLK–
CLK+
tEL
tCPD
DCO–
DDR
DCO+
DCO–
SDR
DCO+
tFCO
FCO–
FCO+
tDATA
tPD
D0–A
BITWISE
MODE
tFRAME
D0+A
D10
N – 17
D08
N – 17
D06
N – 17
D04
N – 17
D02
N – 17
LSB
N – 17
D10
N – 16
D08
N – 16
D06
N – 16
MSB
N – 17
D09
N – 17
D07
N – 17
D05
N – 17
D03
N – 17
D01
N – 17
MSB
N – 16
D09
N – 16
D07
N – 16
D05
N – 17
D04
N – 17
D03
N – 17
D02
N – 17
D01
N – 17
LSB
N – 17
D05
N – 16
D04
N – 16
MSB
N – 17
D10
N – 17
D09
N – 17
D08
N – 17
D07
N – 17
D06
N – 17
MSB
N – 16
D10
N – 16
D04
N – 16
D02
N – 16
LSB
N – 16
D05
N – 16
D03
N – 16
D01
N – 16
D03
N – 16
D02
N – 16
D01
N – 16
LSB
N – 16
D09
N – 16
D08
N – 16
D07
N – 16
D06
N – 16
tLD
D1–A
D1+A
FCO–
FCO+
D0–A
BYTEWISE
MODE
D1–A
D1+A
10065-006
D0+A
Figure 5. 12-Bit DDR/SDR, Two-Lane, 2× Frame Mode
N–1
VIN±x
tA
N
tEH
CLK–
tEL
CLK+
DCO–
tCPD
DCO+
FCO–
tFCO
tFRAME
FCO+
D0+x
tDATA
tPD
MSB
N – 17
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
LSB
0
0
MSB
D14
D13
N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 16 N – 16 N – 16
Figure 6. Wordwise DDR, One-Lane, 1× Frame, 16-Bit Output Mode
Rev. 0 | Page 9 of 40
10065-002
D0–x
AD9253
Data Sheet
N–1
VIN±x
tA
N
tEH
CLK–
tEL
CLK+
DCO–
tCPD
DCO+
FCO–
tFCO
tFRAME
FCO+
MSB
N – 17
D0+x
D10
D9
D8
D7
D6
D5
D4
D3
D2
N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17 N – 17
D1
N – 17
Figure 7. Wordwise DDR, One-Lane, 1× Frame, 12-Bit Output Mode
CLK+
tSSYNC
tHSYNC
SYNC
Figure 8. SYNC Input Timing Requirements
Rev. 0 | Page 10 of 40
D0
MSB
N – 17 N – 16
D10
N – 16
10065-082
tDATA
tPD
10065-079
D0–x
Data Sheet
AD9253
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 6.
Parameter
Electrical
AVDD to AGND
DRVDD to AGND
Digital Outputs
(D0±x, D1±x, DCO+,
DCO−, FCO+, FCO−) to AGND
CLK+, CLK− to AGND
VIN+x, VIN−x to AGND
SCLK/DTP, SDIO/OLM, CSB to AGND
SYNC, PDWN to AGND
RBIAS to AGND
VREF, SENSE to AGND
Environmental
Operating Temperature
Range (Ambient)
Maximum Junction
Temperature
Lead Temperature
(Soldering, 10 sec)
Storage Temperature
Range (Ambient)
Rating
Table 7. Thermal Resistance
−0.3 V to +2.0 V
−0.3 V to +2.0 V
−0.3 V to +2.0 V
Package Type
48-Lead LFCSP
7 mm × 7 mm
(CP-48-13)
−0.3 V to +2.0 V
−0.3 V to +2.0 V
−0.3 V to +2.0 V
−0.3 V to +2.0 V
−0.3 V to +2.0 V
−0.3 V to +2.0 V
1
Air Flow
Velocity
(m/sec)
0.0
1.0
2.5
θJA1
23.7
20.0
18.7
θJB
7.8
N/A
N/A
θJC
7.1
N/A
N/A
Unit
°C/W
°C/W
°C/W
θJA for a 4-layer PCB with solid ground plane (simulated). Exposed pad
soldered to PCB.
ESD CAUTION
−40°C to +85°C
150°C
300°C
−65°C to +150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Rev. 0 | Page 11 of 40
AD9253
Data Sheet
48
47
46
45
44
43
42
41
40
39
38
37
VIN+C
VIN–C
AVDD
AVDD
SYNC
VCM
VREF
SENSE
RBIAS
AVDD
VIN–B
VIN+B
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
AD9253
TOP VIEW
(Not to Scale)
36
35
34
33
32
31
30
29
28
27
26
25
VIN+A
VIN–A
AVDD
PDWN
CSB
SDIO/OLM
SCLK/DTP
DRVDD
D0+A
D0–A
D1+A
D1–A
NOTES
1. THE EXPOSED THERMAL PAD ON THE BOTTOM OF THE
PACKAGE PROVIDES THE ANALOG GROUND FOR THE PART.
THIS EXPOSED PAD MUST BE CONNECTED TO GROUND FOR
PROPER OPERATION.
10065-007
D1–C
D1+C
D0–C
D0+C
DCO–
DCO+
FCO–
FCO+
D1–B
D1+B
D0–B
D0+B
13
14
15
16
17
18
19
20
21
22
23
24
VIN+D 1
VIN–D 2
AVDD 3
AVDD 4
CLK– 5
CLK+ 6
AVDD 7
DRVDD 8
D1–D 9
D1+D 10
D0–D 11
D0+D 12
Figure 9. 48-Lead LFCSP Pin Configuration, Top View
Table 8. Pin Function Descriptions
Pin No.
0
1
2
3, 4, 7, 34, 39, 45, 46
5, 6
8, 29
9, 10
11, 12
13, 14
15, 16
17, 18
19, 20
21, 22
23, 24
25, 26
27, 28
30
31
32
33
Mnemonic
AGND,
Exposed Pad
VIN+D
VIN−D
AVDD
CLK−, CLK+
DRVDD
D1−D, D1+D
D0−D, D0+D
D1−C, D1+C
D0−C, D0+C
DCO−, DCO+
FCO−, FCO+
D1−B, D1+B
D0−B, D0+B
D1−A, D1+A
D0−A, D0+A
SCLK/DTP
SDIO/OLM
CSB
PDWN
35
36
37
38
40
41
42
43
VIN−A
VIN+A
VIN+B
VIN−B
RBIAS
SENSE
VREF
VCM
Description
Analog Ground, Exposed Pad. The exposed thermal pad on the bottom of the package provides the
analog ground for the part. This exposed pad must be connected to ground for proper operation.
ADC D Analog Input True.
ADC D Analog Input Complement.
1.8 V Analog Supply Pins.
Differential Encode Clock. PECL, LVDS, or 1.8 V CMOS inputs.
Digital Output Driver Supply.
Channel D Digital Outputs.
Channel D Digital Outputs.
Channel C Digital Outputs.
Channel C Digital Outputs.
Data Clock Outputs.
Frame Clock Outputs.
Channel B Digital Outputs.
Channel B Digital Outputs.
Channel A Digital Outputs.
Channel A Digital Outputs.
SPI Clock Input/Digital Test Pattern.
SPI Data Input and Output Bidirectional SPI Data/Output Lane Mode.
SPI Chip Select Bar. Active low enable; 30 kΩ internal pull-up.
Digital Input, 30 kΩ Internal Pull-Down.
PDWN high = power-down device.
PDWN low = run device, normal operation.
ADC A Analog Input Complement.
ADC A Analog Input True.
ADC B Analog Input True.
ADC B Analog Input Complement.
Sets Analog Current Bias. Connect to 10 kΩ (1% tolerance) resistor to ground.
Reference Mode Selection.
Voltage Reference Input and Output.
Analog Input Common-Mode Voltage.
Rev. 0 | Page 12 of 40
Data Sheet
Pin No.
44
47
48
AD9253
Mnemonic
SYNC
VIN−C
VIN+C
Description
Digital Input. SYNC input to clock divider.
ADC C Analog Input Complement.
ADC C Analog Input True.
Rev. 0 | Page 13 of 40
AD9253
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
AD9253-80
0
0
AIN = –1dBFS
SNR = 75.5dB
ENOB = 12.07BITS
SFDR = 99.3dBc
–40
–60
–80
–100
–120
5
10
15
20
25
30
35
40
5
0
10
15
20
25
30
35
40
Figure 13. Single-Tone 16k FFT with fIN = 140 MHz, fSAMPLE = 80 MSPS
0
AIN = –1dBFS
SNR = 73.9dB
ENOB = 11.9 BITS
SFDR = 92.7dBc
–20
AIN = –1dBFS
SNR = 70.7dB
ENOB = 11.3 BITS
SFDR = 83.7dBc
–20
–40
AMPLITUDE (dBFS)
–60
–80
–100
–120
–40
–60
–80
–100
5
10
15
20
25
30
35
40
FREQUENCY (MHz)
–140
10065-089
0
0
5
10
15
20
25
30
35
40
FREQUENCY (MHz)
Figure 11. Single-Tone 16k FFT with fIN = 30.5 MHZ, fSAMPLE = 80 MSPS
10065-019
–120
Figure 14. Single-Tone 16k FFT with fIN = 200 MHz, fSAMPLE = 80 MSPS
0
120
AIN = –1dBFS
SNR = 74.7dB
ENOB = 11.9 BITS
SFDR = 94.2dBc
–20
SFDRFS
100
SNR/SFDR (dBFS/dBc)
–40
–60
–80
–100
–120
SNRFS
80
60
SFDR
40
SNR
20
0
5
10
15
20
25
30
35
40
FREQUENCY (MHz)
Figure 12. Single-Tone 16k FFT with fIN = 70 MHz, fSAMPLE = 80 MSPS
–20
–100
10065-017
0
–90
–80
–70
–60
–50
–40
–30
INPUT AMPLITUDE (dBFS)
–20
–10
0
10065-030
AMPLITUDE (dBFS)
–100
FREQUENCY (MHz)
0
AMPLITUDE (dBFS)
–80
–140
Figure 10. Single-Tone 16k FFT with fIN = 9.7 MHz, fSAMPLE = 80 MSPS
–140
–60
10065-018
0
FREQUENCY (MHz)
–140
–40
–120
10065-016
–140
AIN = –1 DBFS
SNR = 72.3dB
ENOB = 11.5 BITS
SFDR = 85dBc
–20
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
–20
Figure 15. SNR/SFDR vs. Analog Input Level, fIN = 9.7 MHz, fSAMPLE = 80 MSPS
Rev. 0 | Page 14 of 40
Data Sheet
AD9253
100
0
AIN1 AND AIN2 = –7dBFS
SFDR = 90.9dBc
IMD2 = 91dBc
IMD3 = 90.9dBc
90
SFDR (dBc)
80
–40
SNR/SFDR (dBFS/dBc)
AMPLITUDE (dBFS)
–20
–60
–80
–100
70
SNR (dBFS)
60
50
40
30
20
–120
5
10
15
20
25
30
35
40
FREQUENCY (MHz)
0
10065-033
0
0
–20
100
SNR/SFDR (dBFS/dBc)
IMD3 (dBc)
–80
80
100
120
140
160
180
200
SFDR (dBc)
95
90
85
80
SFDR (dBFS)
SNR (dBFS)
–100
75
–78
–66
–54
–42
–30
–18
–6
INPUT AMPLITUDE (dBFS)
Figure 17. Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with
fIN1 = 70.5 MHz and fIN2 = 72.5 MHz, fSAMPLE = 80 MSPS
70
–40
–15
10
35
TEMPERATURE (°C)
60
85
10065-042
IMD3 (dBFS)
–120
–90
10065-036
SFDR/IMD3 (dBc/dBFS)
105
–60
60
Figure 18. SNR/SFDR vs. fIN, fSAMPLE = 80 MSPS
0
SFDR (dBc)
40
INPUT FREQUENCY (MHz)
Figure 16. Two-Tone 16k FFT with fIN1 = 70.5 MHz and fIN2 = 72.5 MHz,
fSAMPLE = 80 MSPS
–40
20
10065-039
10
–140
Figure 19. SNR/SFDR vs. Temperature, fIN = 10.3 MHz, fSAMPLE = 80 MSPS
Rev. 0 | Page 15 of 40
AD9253
Data Sheet
AD9253-105
0
0
AIN = –1dBFS
SNR = 75.1dB
ENOB = 12.02 BITS
SFDR = 97.8dBc
–40
–60
–80
–100
10
20
30
40
50
0
10
20
30
40
50
Figure 23. Single-Tone 16k FFT with fIN = 140 MHz, fSAMPLE = 105 MSPS
0
AIN = –1dBFS
SNR = 74dB
ENOB = 11.9 BITS
SFDR = 92.1dBc
–20
AIN = –1dBFS
SNR = 71.2dB
ENOB = 11.3 BITS
SFDR = 82dBc
–20
–40
AMPLITUDE (dBFS)
–60
–80
–100
–120
–40
–60
–80
–100
10
20
30
40
50
FREQUENCY (MHz)
Figure 21. Single-Tone 16k FFT with fIN = 30.5 MHZ, fSAMPLE = 105 MSPS
–140
10
20
30
40
50
FREQUENCY (MHz)
Figure 24. Single-Tone 16k FFT with fIN = 200 MHz, fSAMPLE = 105 MSPS
0
120
AIN = –1dBFS
SNR = 73.4dB
ENOB = 11.9 BITS
SFDR = 89.8dBc
–20
0
10065-023
0
10065-090
–120
SFDRFS
100
SNR/SFDR (dBFS/dBc)
–40
–60
–80
–100
–120
SNRFS
80
60
SFDR
40
SNR
20
0
10
20
30
FREQUENCY (MHz)
40
50
10065-021
0
Figure 22. Single-Tone 16k FFT with fIN = 70 MHz, fSAMPLE = 105 MSPS
–20
–100
–90
–80
–70
–60
–50
–40
–30
INPUT AMPLITUDE (dBFS)
–20
–10
0
10065-031
AMPLITUDE (dBFS)
–100
FREQUENCY (MHz)
0
AMPLITUDE (dBFS)
–80
–140
10065-020
0
Figure 20. Single-Tone 16k FFT with fIN = 9.7 MHz, fSAMPLE = 105 MSPS
–140
–60
–120
FREQUENCY (MHz)
–140
–40
10065-022
–120
–140
AIN = –1dBFS
SNR = 73.1dB
ENOB = 11.6 BITS
SFDR = 85dBc
–20
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
–20
Figure 25. SNR/SFDR vs. Analog Input Level, fIN = 9.7 MHz, fSAMPLE = 105 MSPS
Rev. 0 | Page 16 of 40
Data Sheet
AD9253
100
0
AIN1 AND AIN2 = –7dBFS
SFDR = 87.5dBc
IMD2 = 92.6dBc
IMD3 = 87.5dBc
90
SFDR (dBc)
80
–40
SNR/SFDR (dBFS/dBc)
AMPLITUDE (dBFS)
–20
–60
–80
–100
70
SNR (dBFS)
60
50
40
30
20
–120
10
20
30
40
0
10065-034
0
50
FREQUENCY (MHz)
0
20
40
60
80
100
120
140
160
180
200
INPUT FREQUENCY (MHz)
Figure 26. Two-Tone 16k FFT with fIN1 = 70.5 MHz and fIN2 = 72.5 MHz,
fSAMPLE = 105 MSPS
10065-040
10
–140
Figure 28. SNR/SFDR vs. fIN, fSAMPLE = 105 MSPS
0
100
–20
95
SNR/SFDR (dBFS/dBc)
SFDR (dBc)
–40
IMD3 (dBc)
–60
–80
90
85
80
SNR (dBFS)
SFDR (dBFS)
–100
75
–78
–66
–54
–42
–30
–18
–6
INPUT AMPLITUDE (dBFS)
Figure 27. Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with
fIN1 = 70.5 MHz and fIN2 = 72.5 MHz, fSAMPLE = 105 MSPS
70
–40
–15
10
35
TEMPERATURE (°C)
60
85
10065-043
IMD3 (dBFS)
–120
–90
10065-037
SFDR/IMD3 (dBc/dBFS)
SFDR (dBc)
Figure 29. SNR/SFDR vs. Temperature, fIN = 10.3 MHz, fSAMPLE = 105 MSPS
Rev. 0 | Page 17 of 40
AD9253
Data Sheet
AD9253-125
0
0
AIN = –1dBFS
SNR = 75.3dB
ENOB = 12.04 BITS
SFDR = 98.52dBc
–40
–60
–80
–100
–120
10
20
30
40
50
60
Figure 30. Single-Tone 16k FFT with fIN = 9.7 MHz, fSAMPLE = 125 MSPS
0
10
20
30
40
50
60
Figure 33. Single-Tone 16k FFT with fIN = 140 MHz, fSAMPLE = 125 MSPS
0
AIN = –1dBFS
SNR = 70.6dB
ENOB = 11.2 BITS
SFDR = 83.2dBc
–20
–40
AMPLITUDE (dBFS)
–60
–80
–100
–40
–60
–80
–100
10
20
30
40
50
60
FREQUENCY (MHz)
–140
10065-091
0
Figure 31. Single-Tone 16k FFT with fIN = 30.5 MHZ, fSAMPLE = 125 MSPS
0
10
20
30
40
50
60
FREQUENCY (MHz)
10065-027
–120
–120
Figure 34. Single-Tone 16k FFT with fIN = 200 MHz, fSAMPLE = 125 MSPS
0
0
AIN = –1dBFS
SNR = 73.2dB
ENOB = 11.9 BITS
SFDR = 91.2dBc
–20
AIN = –1dBFS
SNR = 72.4dB
ENOB = 11.7 BITS
SFDR = 88.4dBc
–20
AMPLITUDE (dBFS)
–40
–60
–80
–100
–40
–60
–80
–100
–120
–120
10
20
30
40
FREQUENCY (MHz)
50
60
–140
10065-025
0
Figure 32. Single-Tone 16k FFT with fIN = 70 MHz, fSAMPLE = 125 MSPS
0
10
20
30
40
FREQUENCY (MHz)
50
60
10065-081
AMPLITUDE (dBFS)
–100
FREQUENCY (MHz)
AIN = –1dBFS
SNR = 74.2dB
ENOB = 12 BITS
SFDR = 92.5dBc
–20
AMPLITUDE (dBFS)
–80
–140
0
–140
–60
10065-026
0
FREQUENCY (MHz)
–140
–40
–120
10065-024
–140
AIN = –1dBFS
SNR = 73.1dB
ENOB = 11.6 BITS
SFDR = 85dBc
–20
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
–20
Figure 35. Single-Tone 16k FFT with fIN = 140 MHz at fSAMPLE = 122.88 MSPS
Rev. 0 | Page 18 of 40
Data Sheet
AD9253
100
120
90
SFDRFS
SFDR (dBc)
80
SNR/SFDR (dBFS/dBc)
SNR/SFDR (dBFS/dBc)
100
SNRFS
80
60
SFDR
40
SNR
70
SNR (dBFS)
60
50
40
30
20
20
–80
–70
–60
–50
–40
–30
–20
–10
0
INPUT AMPLITUDE (dBFS)
0
10065-032
–90
0
40
60
80
100
120
140
160
180
200
INPUT FREQUENCY (MHz)
Figure 36. SNR/SFDR vs. Analog Input Level, fIN = 9.7 MHz, fSAMPLE = 125 MSPS
Figure 39. SNR/SFDR vs. fIN, fSAMPLE = 125 MSPS
0
100
SFDR (dBc)
AIN1 AND AIN2 = –7dBFS
SFDR = 86.2dBc
IMD2 = 98.3dBc
IMD3 = 86.2dBc
–20
95
–40
SNR/SFDR (dBFS/dBc)
AMPLITUDE (dBFS)
20
10065-041
10
0
–100
–60
–80
–100
90
85
80
SNR (dBFS)
0
10
20
30
40
50
60
FREQUENCY (MHz)
70
–40
10065-035
–140
Figure 37. Two-Tone 16k FFT with fIN1 = 70.5 MHz and fIN2 = 72.5 MHz,
fSAMPLE = 125 MSPS
–15
10
35
60
85
TEMPERATURE (°C)
10065-044
75
–120
Figure 40. SNR/SFDR vs. Temperature, fIN = 10.3 MHz, fSAMPLE = 125 MSPS
2.5
0
2.0
1.5
SFDR (dBc)
1.0
INL (LSB)
–40
IMD3 (dBc)
–60
–80
0
–0.5
–1.5
–100
–78
–66
–54
–42
–30
–18
–6
INPUT AMPLITUDE (dBFS)
–2.5
0
2000
4000
6000
8000
10000
12000 14000
OUTPUT CODE
Figure 41. INL, fIN = 9.7 MHz, fSAMPLE = 125 MSPS
Figure 38. Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with
fIN1 = 70.5 MHz and fIN2 = 72.5 MHz, fSAMPLE = 125 MSPS
Rev. 0 | Page 19 of 40
16000
10065-045
–2.0
IMD3 (dBFS)
–120
–90
0.5
–1.0
SFDR (dBFS)
10065-038
SFDR/IMD3 (dBc/dBFS)
–20
AD9253
Data Sheet
1.0
105
SFDR
0.8
100
0.6
SNR/SFDR (dBFS/dBc)
95
0.4
DNL (LSB)
0.2
0
–0.2
–0.4
90
85
80
SNRFS
75
–0.6
0
2000
4000
6000
8000
10000
12000 14000
65
20
10065-046
–1.0
16000
OUTPUT CODE
45
70
95
120
SAMPLE FREQUENCY (MSPS)
10065-028
70
–0.8
Figure 45. SNR/SFDR vs. Encode, fIN = 9.7 MHz, fSAMPLE = 125 MSPS
Figure 42. DNL, fIN = 9.7 MHz, fSAMPLE = 125 MSPS
500,000
105
450,000
0.94 LSB rms
100
400,000
95
SNR/SFDR (dBFS/dBc)
300,000
250,000
200,000
150,000
100,000
N
10065-050
N–4 N–3 N–2 N–1
N+1 N+2 N+3 N+4 N+5
CODE
100
DRVDD
80
60
50
AVDD
30
20
10
0
1
10
FREQUENCY (MHz)
10065-087
PSRR (dB)
70
40
85
80
SNRFS
75
65
20
45
70
95
120
SAMPLE FREQUENCY (MSPS)
Figure 46. SNR/SFDR vs. Encode, fIN = 70 MHz, fSAMPLE = 125 MSPS
Figure 43. Input-Referred Noise Histogram, fSAMPLE = 125 MSPS
90
90
70
50,000
0
SFDR
Figure 44. PSRR vs. Frequency, fCLK = 125 MHz, fSAMPLE = 125 MSPS
Rev. 0 | Page 20 of 40
10065-029
NUMBER OF HITS
350,000
Data Sheet
AD9253
EQUIVALENT CIRCUITS
AVDD
AVDD
350Ω
SCLK/DTP, SYNC,
AND PDWN
30kΩ
10065-012
10065-008
VIN±x
Figure 47. Equivalent Analog Input Circuit
Figure 51. Equivalent SCLK/DTP, SYNC, and PDWN Input Circuit
AVDD
5Ω
CLK+
AVDD
15kΩ
0.9V
AVDD
15kΩ
10065-009
10065-013
5Ω
CLK–
375Ω
RBIAS
AND VCM
Figure 52. Equivalent RBIAS and VCM Circuit
Figure 48. Equivalent Clock Input Circuit
AVDD
AVDD
30kΩ
350Ω
SDIO/OLM
30kΩ
30kΩ
350Ω
10065-010
10065-014
CSB
Figure 53. Equivalent CSB Input Circuit
Figure 49. Equivalent SDIO/OLM Input Circuit
DRVDD
V
AVDD
V
D0–x, D1–x
D0+x, D1+x
V
V
375Ω
VREF
10065-015
DRGND
10065-011
7.5kΩ
Figure 50. Equivalent Digital Output Circuit
Figure 54. Equivalent VREF Circuit
Rev. 0 | Page 21 of 40
AD9253
Data Sheet
THEORY OF OPERATION
The AD9253 is a multistage, pipelined ADC. Each stage
provides sufficient overlap to correct for flash errors in the
preceding stage. The quantized outputs from each stage are
combined into a final 14-bit result in the digital correction
logic. The serializer transmits this converted data in a 16-bit
output. The pipelined architecture permits the first stage to
operate with a new input sample while the remaining stages
operate with preceding samples. Sampling occurs on the rising
edge of the clock.
Each stage of the pipeline, excluding the last, consists of a low
resolution flash ADC connected to a switched-capacitor DAC
and an interstage residue amplifier (for example, a multiplying
digital-to-analog converter (MDAC)). The residue amplifier
magnifies the difference between the reconstructed DAC output
and the flash input for the next stage in the pipeline. One bit of
redundancy is used in each stage to facilitate digital correction
of flash errors. The last stage simply consists of a flash ADC.
The output staging block aligns the data, corrects errors, and
passes the data to the output buffers. The data is then serialized
and aligned to the frame and data clocks.
ANALOG INPUT CONSIDERATIONS
The analog input to the AD9253 is a differential switchedcapacitor circuit designed for processing differential input
signals. This circuit can support a wide common-mode range
while maintaining excellent performance. By using an input
common-mode voltage of midsupply, users can minimize
signal-dependent errors and achieve optimum performance.
the output stage of the driving source. In addition, low Q inductors
or ferrite beads can be placed on each leg of the input to reduce
high differential capacitance at the analog inputs and therefore
achieve the maximum bandwidth of the ADC. Such use of low
Q inductors or ferrite beads is required when driving the converter
front end at high IF frequencies. Either a differential capacitor or
two single-ended capacitors can be placed on the inputs to
provide a matching passive network. This ultimately creates a
low-pass filter at the input to limit unwanted broadband noise.
See the AN-742 Application Note, the AN-827 Application Note,
and the Analog Dialogue article “Transformer-Coupled FrontEnd for Wideband A/D Converters” (Volume 39, April 2005) for
more information. In general, the precise values depend on the
application.
Input Common Mode
The analog inputs of the AD9253 are not internally dc-biased.
Therefore, in ac-coupled applications, the user must provide
this bias externally. Setting the device so that VCM = AVDD/2 is
recommended for optimum performance, but the device can
function over a wider range with reasonable performance, as
shown in Figure 56.
An on-chip, common-mode voltage reference is included in the
design and is available from the VCM pin. The VCM pin must
be decoupled to ground by a 0.1 μF capacitor, as described in
the Applications Information section.
Maximum SNR performance is achieved by setting the ADC to
the largest span in a differential configuration. In the case of the
AD9253, the largest input span available is 2 V p-p.
100
CPAR
80
SNR/SFDR (dBFS/dBc)
H
VIN+x
CSAMPLE
S
S
S
S
CSAMPLE
VIN–x
H
10065-051
H
CPAR
SFDR
90
H
SNRFS
70
60
50
40
30
The clock signal alternately switches the input circuit between
sample mode and hold mode (see Figure 55). When the input
circuit is switched to sample mode, the signal source must be
capable of charging the sample capacitors and settling within
one-half of a clock cycle. A small resistor in series with each
input can help reduce the peak transient current injected from
Rev. 0 | Page 22 of 40
20
0.5
0.7
0.9
1.1
VCM (V)
Figure 56. SNR/SFDR vs. Common-Mode Voltage,
fIN = 9.7 MHz, fSAMPLE = 125 MSPS
1.3
10065-052
Figure 55. Switched-Capacitor Input Circuit
Data Sheet
AD9253
Differential Input Configurations
Internal Reference Connection
There are several ways to drive the AD9253 either actively or
passively. However, optimum performance is achieved by driving
the analog inputs differentially. Using a differential double balun
configuration to drive the AD9253 provides excellent performance
and a flexible interface to the ADC (see Figure 58) for baseband
applications.
A comparator within the AD9253 detects the potential at the
SENSE pin and configures the reference into two possible
modes, which are summarized in Table 9. If SENSE is grounded,
the reference amplifier switch is connected to the internal resistor
divider (see Figure 57), setting VREF to 1.0 V.
Table 9. Reference Configuration Summary
For applications where SNR is a key parameter, differential transformer coupling is the recommended input configuration (see
Figure 59), because the noise performance of most amplifiers is
not adequate to achieve the true performance of the AD9253.
SENSE
Voltage (V)
AGND to
0.2
AVDD
Selected Mode
Fixed Internal
Reference
Fixed External
Reference
Regardless of the configuration, the value of the shunt capacitor,
C, is dependent on the input frequency and may need to be
reduced or removed.
It is not recommended to drive the AD9253 inputs single-ended.
Resulting
VREF (V)
1.0 internal
1.0 applied
to external
VREF pin
Resulting
Differential
Span (V p-p)
2.0
2.0
VIN+A/VIN+B
VOLTAGE REFERENCE
VIN–A/VIN–B
A stable and accurate 1.0 V voltage reference is built into the
AD9253. VREF can be configured using either the internal 1.0 V
reference or an externally applied 1.0 V reference voltage. The
various reference modes are summarized in the Internal Reference
Connection section and the External Reference Operation
section. The VREF pin should be externally decoupled to
ground with a low ESR, 1.0 μF capacitor in parallel with a low
ESR, 0.1 μF ceramic capacitor.
ADC
CORE
VREF
1.0µF
0.1µF
SELECT
LOGIC
SENSE
ADC
Figure 57. Internal Reference Configuration
0.1µF
0.1µF
C
2V p-p
R
33Ω
*C1
C
0.1µF
ET1-1-I3
VIN+x
33Ω
ADC
5pF
33Ω
R
VCM
VIN–x
33Ω
C
*C1
200Ω
0.1µF
C
0.1µF
*C1 IS OPTIONAL
Figure 58. Differential Double Balun Input Configuration for Baseband Applications
ADT1-1WT
1:1 Z RATIO
R
*C1
VIN+x
33Ω
49.9Ω
C
R
33Ω
ADC
5pF
VIN–x
VCM
*C1
200Ω
0.1µF
0.1μF
*C1 IS OPTIONAL
Figure 59. Differential Transformer-Coupled Configuration
for Baseband Applications
Rev. 0 | Page 23 of 40
10065-056
2V p-p
10065-059
R
10065-060
0.5V
AD9253
Data Sheet
If the internal reference of the AD9253 is used to drive multiple
converters to improve gain matching, the loading of the reference
by the other converters must be considered. Figure 60 shows
how the internal reference voltage is affected by loading.
0
–0.5
–1.0
–2.5
–3.0
–3.5
–4.0
0.5
1.0
1.5
2.0
2.5
3.0
LOAD CURRENT (mA)
Figure 60. VREF Error vs. Load Current
External Reference Operation
The use of an external reference may be necessary to enhance
the gain accuracy of the ADC or improve thermal drift characteristics. Figure 61 shows the typical drift characteristics of the
internal reference in 1.0 V mode.
This limit helps prevent the large voltage swings of the clock
from feeding through to other portions of the AD9253 while
preserving the fast rise and fall times of the signal that are critical
to achieving low jitter performance. However, the diode
capacitance comes into play at frequencies above 500 MHz. Care
must be taken in choosing the appropriate signal limiting diode.
4
Mini-Circuits®
ADT1-1WT, 1:1 Z
CLOCK
INPUT
VREF ERROR (mV)
2
0.1µF
XFMR
0.1µF
CLK+
100Ω
50Ω
ADC
0.1µF
0
CLK–
SCHOTTKY
DIODES:
HSMS2822
0.1µF
–2
10065-064
0
10065-061
–4.5
The RF balun configuration is recommended for clock frequencies
between 125 MHz and 1 GHz, and the RF transformer is recommended for clock frequencies from 10 MHz to 200 MHz. The
back-to-back Schottky diodes across the transformer/balun
secondary winding limit clock excursions into the AD9253 to
approximately 0.8 V p-p differential.
Figure 62. Transformer-Coupled Differential Clock (Up to 200 MHz)
–4
–6
0.1µF
–8
–40
–15
10
35
60
TEMPERATURE (°C)
85
10065-062
CLOCK
INPUT
It is not recommended to leave the SENSE pin floating.
CLOCK INPUT CONSIDERATIONS
For optimum performance, clock the AD9253 sample clock
inputs, CLK+ and CLK−, with a differential signal. The signal
is typically ac-coupled into the CLK+ and CLK− pins via a
transformer or capacitors. These pins are biased internally
(see Figure 48) and require no external bias.
CLK+
50Ω
ADC
0.1µF
0.1µF
CLK–
SCHOTTKY
DIODES:
HSMS2822
Figure 61. Typical VREF Drift
When the SENSE pin is tied to AVDD, the internal reference is
disabled, allowing the use of an external reference. An internal
reference buffer loads the external reference with an equivalent
7.5 kΩ load (see Figure 54). The internal buffer generates the
positive and negative full-scale references for the ADC core. Therefore, the external reference must be limited to a maximum of 1.0 V.
0.1µF
10065-065
VREF ERROR (%)
–2.0
–5.0
The AD9253 has a flexible clock input structure. The clock input
can be a CMOS, LVDS, LVPECL, or sine wave signal.
Regardless of the type of signal being used, clock source jitter is
of the most concern, as described in the Jitter Considerations
section.
Figure 62 and Figure 63 show two preferred methods for clocking the AD9253 (at clock rates up to 1 GHz prior to internal CLK
divider). A low jitter clock source is converted from a singleended signal to a differential signal using either an RF transformer
or an RF balun.
INTERNAL VREF = 1V
–1.5
Clock Input Options
Figure 63. Balun-Coupled Differential Clock (Up to 1 GHz)
If a low jitter clock source is not available, another option is to
ac couple a differential PECL signal to the sample clock input
pins, as shown in Figure 65. The AD9510/AD9511/AD9512/
AD9513/AD9514/AD9515/AD9516/AD9517 clock drivers offer
excellent jitter performance.
A third option is to ac couple a differential LVDS signal to the
sample clock input pins, as shown in Figure 66. The AD9510/
AD9511/AD9512/AD9513/AD9514/AD9515/AD9516/AD9517
clock drivers offer excellent jitter performance.
In some applications, it may be acceptable to drive the sample
clock inputs with a single-ended 1.8 V CMOS signal. In such
applications, drive the CLK+ pin directly from a CMOS gate, and
Rev. 0 | Page 24 of 40
Data Sheet
AD9253
bypass the CLK− pin to ground with a 0.1 μF capacitor (see
Figure 67).
80
Input Clock Divider
75
SNRFS (dBFS)
The AD9253 contains an input clock divider with the ability
to divide the input clock by integer values between 1 and 8.
The AD9253 clock divider can be synchronized using the
external SYNC input. Bit 0 and Bit 1 of Register 0x109 allow the
clock divider to be resynchronized on every SYNC signal or
only on the first SYNC signal after the register is written. A
valid SYNC causes the clock divider to reset to its initial state.
This synchronization feature allows multiple parts to have their
clock dividers aligned to guarantee simultaneous input sampling.
SNRFS (DCS ON)
SNRFS (DCS OFF)
70
65
55
40
42
44
46
48
50
52
54
DUTY CYCLE (%)
Clock Duty Cycle
0.1µF
0.1µF
CLK+
50kΩ
AD951x
PECL DRIVER
240Ω
50kΩ
100Ω
0.1µF
ADC
CLK–
10065-066
CLOCK
INPUT
240Ω
Figure 65. Differential PECL Sample Clock (Up to 1 GHz)
0.1µF
CLOCK
INPUT
50kΩ
AD951x
LVDS DRIVER
100Ω
0.1µF
ADC
CLK–
10065-067
CLOCK
INPUT
0.1µF
CLK+
0.1µF
50kΩ
Figure 66. Differential LVDS Sample Clock (Up to 1 GHz)
VCC
0.1µF
50Ω1
1kΩ
AD951x
CMOS DRIVER
OPTIONAL
0.1µF
100Ω
1kΩ
CLK+
ADC
CLK–
0.1µF
150Ω RESISTOR IS OPTIONAL.
Figure 67. Single-Ended 1.8 V CMOS Input Clock (Up to 200 MHz)
Rev. 0 | Page 25 of 40
10065-068
CLOCK
INPUT
60
Jitter in the rising edge of the input is still of concern and is not
easily reduced by the internal stabilization circuit. The duty
cycle control loop does not function for clock rates less than
20 MHz, nominally. The loop has a time constant associated
with it that must be considered in applications in which the
clock rate can change dynamically. A wait time of 1.5 μs to 5 μs
is required after a dynamic clock frequency increase or decrease
before the DCS loop is relocked to the input signal.
The AD9253 contains a duty cycle stabilizer (DCS) that retimes
the nonsampling (falling) edge, providing an internal clock
signal with a nominal 50% duty cycle. This allows the user to
provide a wide range of clock input duty cycles without affecting
the performance of the AD9253. Noise and distortion performance are nearly flat for a wide range of duty cycles with the DCS
on, as shown in Figure 64.
0.1µF
58
Figure 64. SNR vs. DCS On/Off
Typical high speed ADCs use both clock edges to generate a variety of internal timing signals and, as a result, may be sensitive to
clock duty cycle. Commonly, a ±5% tolerance is required on the
clock duty cycle to maintain dynamic performance characteristics.
CLOCK
INPUT
56
10065-069
60
AD9253
Data Sheet
Jitter Considerations
POWER DISSIPATION AND POWER-DOWN MODE
High speed, high resolution ADCs are sensitive to the quality of the
clock input. The degradation in SNR at a given input frequency
(fA) due only to aperture jitter (tJ) can be calculated by
As shown in Figure 69, the power dissipated by the AD9253 is
proportional to its sample rate. The digital power dissipation
does not vary significantly because it is determined primarily by
the DRVDD supply and bias current of the LVDS output drivers.




350
The clock input should be treated as an analog signal in cases
where aperture jitter may affect the dynamic range of the AD9253.
Power supplies for clock drivers should be separated from the
ADC output driver supplies to avoid modulating the clock signal
with digital noise. Low jitter, crystal-controlled oscillators make
the best clock sources. If the clock is generated from another
type of source (by gating, dividing, or other methods), it should
be retimed by the original clock at the last step.
RMS CLOCK JITTER REQUIREMENT
90
14 BITS
80
12 BITS
70
10 BITS
60
8 BITS
50
40
0.125ps
0.25ps
0.5ps
1.0ps
2.0ps
30
1
10
100
ANALOG INPUT FREQUENCY (MHz)
Figure 68. Ideal SNR vs. Input Frequency and Jitter
1000
10065-070
SNR (dB)
110
16 BITS
250
105 MSPS
80 MSPS
200
65 MSPS
50 MSPS
150
40 MSPS
20 MSPS
100
10
20
30
40
50
60
70
80
90
100 110 120 130
SAMPLE RATE (MSPS)
The AD9253 is placed in power-down mode either by the SPI
port or by asserting the PDWN pin high. In this state, the ADC
typically dissipates 2 mW. During power-down, the output
drivers are placed in a high impedance state. Asserting the
PDWN pin low returns the AD9253 to its normal operating
mode. Note that PDWN is referenced to the digital output
driver supply (DRVDD) and should not exceed that supply
voltage.
120
100
125 MSPS
Figure 69. Analog Core Power vs. fSAMPLE for fIN = 10.3 MHz
Refer to the AN-501 Application Note and the AN-756
Application Note for more in-depth information about jitter
performance as it relates to ADCs.
130
300
10065-071
In this equation, the rms aperture jitter represents the root mean
square of all jitter sources, including the clock input, analog input
signal, and ADC aperture jitter specifications. IF undersampling
applications are particularly sensitive to jitter (see Figure 68).
ANALOG CORE POWER (mW)

1
SNR Degradation = 20 log10 
 2  f A  t J
Low power dissipation in power-down mode is achieved by
shutting down the reference, reference buffer, biasing networks,
and clock. Internal capacitors are discharged when entering
power-down mode and then must be recharged when returning
to normal operation. As a result, wake-up time is related to the
time spent in power-down mode, and shorter power-down
cycles result in proportionally shorter wake-up times. When
using the SPI port interface, the user can place the ADC in
power-down mode or standby mode. Standby mode allows the
user to keep the internal reference circuitry powered when
faster wake-up times are required. See the Memory Map section
for more details on using these features.
Rev. 0 | Page 26 of 40
Data Sheet
AD9253
DIGITAL OUTPUTS AND TIMING
When operating in reduced range mode, the output current is
reduced to 2 mA. This results in a 200 mV swing (or 400 mV p-p
differential) across a 100 Ω termination at the receiver.
D0 400mV/DIV
D1 400mV/DIV
DCO 400mV/DIV
FCO 400mV/DIV
4ns/DIV
Figure 71. AD9253-125, LVDS Output Timing Example in Reduced Range Mode
An example of the LVDS output using the ANSI-644 standard
(default) data eye and a time interval error (TIE) jitter histogram with trace lengths less than 24 inches on standard FR-4
material is shown in Figure 72.
500
EYE: ALL BITS
ULS: 7000/400354
400
EYE DIAGRAM VOLTAGE (mV)
The AD9253 LVDS outputs facilitate interfacing with LVDS
receivers in custom ASICs and FPGAs for superior switching
performance in noisy environments. Single point-to-point net
topologies are recommended with a 100 Ω termination resistor
placed as close to the receiver as possible. If there is no far-end
receiver termination or there is poor differential trace routing,
timing errors may result. To avoid such timing errors, it is
recommended that the trace length be less than 24 inches and
that the differential output traces be close together and at equal
lengths. An example of the FCO and data stream with proper
trace length and position is shown in Figure 70. Figure 71 shows
the LVDS output timing example in reduced range mode.
10065-083
The AD9253 differential outputs conform to the ANSI-644 LVDS
standard on default power-up. This can be changed to a low power,
reduced signal option (similar to the IEEE 1596.3 standard) via the
SPI. The LVDS driver current is derived on chip and sets the
output current at each output equal to a nominal 3.5 mA. A 100 Ω
differential termination resistor placed at the LVDS receiver
inputs results in a nominal 350 mV swing (or 700 mV p-p
differential) at the receiver.
300
200
100
0
–100
–200
–300
–400
–500
–0.8ns
–0.4ns
0ns
0.4ns
0.8ns
7k
Figure 70. AD9253-125, LVDS Output Timing Example in ANSI-644 Mode (Default)
5k
4k
3k
2k
1k
0
200ps
250ps
300ps
350ps
400ps
450ps
500ps
10065-075
4ns/DIV
TIE JITTER HISTOGRAM (Hits)
D0 500mV/DIV
D1 500mV/DIV
DCO 500mV/DIV
FCO 500mV/DIV
10065-074
6k
Figure 72. Data Eye for LVDS Outputs in ANSI-644 Mode with Trace Lengths
Less than 24 Inches on Standard FR-4 Material, External 100 Ω Far-End
Termination Only
Rev. 0 | Page 27 of 40
AD9253
500
Data Sheet
EYE: ALL BITS
Figure 73 shows an example of trace lengths exceeding 24 inches
on standard FR-4 material. Notice that the TIE jitter histogram
reflects the decrease of the data eye opening as the edge deviates
from the ideal position.
It is the user’s responsibility to determine if the waveforms
meet the timing budget of the design when the trace lengths
exceed 24 inches. Additional SPI options allow the user to further
increase the internal termination (increasing the current) of all
four outputs to drive longer trace lengths. This can be achieved
by programming Register 0x15. Even though this produces
sharper rise and fall times on the data edges and is less prone to
bit errors, the power dissipation of the DRVDD supply increases
when this option is used.
ULS: 8000/414024
EYE DIAGRAM VOLTAGE (mV)
400
300
200
100
0
–100
–200
–300
–400
–500
–0.8ns
–0.4ns
0ns
0.4ns
–0.8ns
The format of the output data is twos complement by default.
An example of the output coding format can be found in Table 10.
To change the output data format to offset binary, see the
Memory Map section.
12k
TIE JITTER HISTOGRAM (Hits)
10k
Data from each ADC is serialized and provided on a separate
channel in two lanes in DDR mode. The data rate for each serial
stream is equal to 16 bits times the sample clock rate, with a
maximum of 500 Mbps/lane [(16 bits × 125 MSPS)/(2 × 2) =
500 Mbps/lane)]. The lowest typical conversion rate is 10 MSPS.
See the Memory Map section for details on enabling this feature.
8k
6k
4k
0k
–800ps –600ps –400ps –200ps
0ps
200ps
400ps
600ps
10065-076
2k
Figure 73. Data Eye for LVDS Outputs in ANSI-644 Mode with Trace Lengths
Greater than 24 Inches on Standard FR-4 Material, External 100 Ω Far-End
Termination Only
Two output clocks are provided to assist in capturing data from
the AD9253. The DCO is used to clock the output data and is
equal to four times the sample clock (CLK) rate for the default
mode of operation. Data is clocked out of the AD9253 and must
be captured on the rising and falling edges of the DCO that
supports double data rate (DDR) capturing. The FCO is used to
signal the start of a new output byte and is equal to the sample
clock rate in 1× frame mode. See the Timing Diagrams section
for more information.
Table 10. Digital Output Coding
Input (V)
VIN+ − VIN−
VIN+ − VIN−
VIN+ − VIN−
VIN+ − VIN−
VIN+ − VIN−
Condition (V)
<−VREF − 0.5 LSB
−VREF
0V
+VREF − 1.0 LSB
>+VREF − 0.5 LSB
Offset Binary Output Mode
0000 0000 0000 0000
0000 0000 0000 0000
1000 0000 0000 0000
1111 1111 1111 1100
1111 1111 1111 1100
Rev. 0 | Page 28 of 40
Twos Complement Mode
1000 0000 0000 0000
1000 0000 0000 0000
0000 0000 0000 0000
0111 1111 1111 1100
0111 1111 1111 1100
Data Sheet
AD9253
Table 11. Flexible Output Test Modes
Output Test
Mode
Bit Sequence
0000
0001
Digital Output Word 2
N/A
N/A
N/A
Yes
N/A
Yes
0101 0101 0101 (12-bit)
0101 0101 0101 0100 (16-bit)
N/A
No
PN sequence long 1
Digital Output Word 1
N/A
1000 0000 0000 (12-bit)
1000 0000 0000 0000 (16-bit)
1111 1111 1111 (12-bit)
0000 0000 0000 0000 (16-bit)
0000 0000 0000 (12-bit)
0000 0000 0000 0000 (16-bit)
1010 1010 1010 (12-bit)
1010 1010 1010 1010 (16-bit)
N/A
Subject to
Data Format
Select
N/A
Yes
Pattern Name
Off (default)
Midscale short
0010
+Full-scale short
0011
−Full-scale short
0100
Checkerboard
0101
0110
PN sequence short1
N/A
N/A
Yes
0111
0000 0000 0000 (12-bit)
0000 0000 0000 0000 (16-bit)
Register 0x1B to Register 0x1C
N/A
1010
1× sync
N/A
No
1011
One bit high
1111 1111 1111 (12-bit)
111 1111 1111 1100 (16-bit)
Register 0x19 to Register 0x1A
1010 1010 1010 (12-bit)
1010 1010 1010 1000 (16-bit)
0000 0011 1111 (12-bit)
0000 0001 1111 1100 (16-bit)
1000 0000 0000 (12-bit)
1000 0000 0000 0000 (16-bit)
No
1000
1001
One-/zero-word
toggle
User input
1-/0-bit toggle
N/A
No
1100
Mixed frequency
1010 0011 0011 (12-bit)
1010 0001 1001 1100 (16-bit)
N/A
No
1
Yes
Notes
Offset binary
code shown
Offset binary
code shown
Offset binary
code shown
PN23
ITU 0.150
X23 + X18 + 1
PN9
ITU 0.150
X 9 + X5 + 1
No
No
Pattern
associated
with the
external pin
All test mode options except PN sequence short and PN sequence long can support 12-bit to 16-bit word lengths to verify data capture to the receiver.
When the SPI is used, the DCO phase can be adjusted in 60°
increments relative to the data edge. This enables the user to
refine system timing margins if required. The default DCO+
and DCO− timing, as shown in Figure 2, is 90° relative to the
output data edge.
A 12-bit serial stream can also be initiated from the SPI. This
allows the user to implement and test compatibility to lower
resolution systems. When changing the resolution to a 12-bit
serial stream, the data stream is shortened. See Figure 3 for the
12-bit example. However, in the default option with the serial
output number of bits at 16, the data stream stuffs two 0s at the
end of the 14-bit serial data.
In default mode, as shown in Figure 2, the MSB is first in the
data output serial stream. This can be inverted so that the LSB is
first in the data output serial stream by using the SPI.
There are 12 digital output test pattern options available that
can be initiated through the SPI. This is a useful feature when
validating receiver capture and timing. Refer to Table 11 for the
output bit sequencing options available. Some test patterns have
two serial sequential words and can be alternated in various
ways, depending on the test pattern chosen. Note that some
patterns do not adhere to the data format select option. In
addition, custom user-defined test patterns can be assigned in
the 0x19, 0x1A, 0x1B, and 0x1C register addresses.
The PN sequence short pattern produces a pseudorandom bit
sequence that repeats itself every 29 − 1 or 511 bits. A
description of the PN sequence and how it is generated can be
found in Section 5.1 of the ITU-T 0.150 (05/96) standard. The
seed value is all 1s (see Table 12 for the initial values). The
output is a parallel representation of the serial PN9 sequence in
MSB-first format. The first output word is the first 14 bits of the
PN9 sequence in MSB aligned form.
The PN sequence long pattern produces a pseudorandom bit
sequence that repeats itself every 223 − 1 or 8,388,607 bits. A
description of the PN sequence and how it is generated can be
found in Section 5.6 of the ITU-T 0.150 (05/96) standard. The
seed value is all 1s (see Table 12 for the initial values) and the
AD9253 inverts the bit stream with relation to the ITU standard.
The output is a parallel representation of the serial PN23 sequence
in MSB-first format. The first output word is the first 14 bits of the
PN23 sequence in MSB aligned form
Rev. 0 | Page 29 of 40
AD9253
Data Sheet
Table 12. PN Sequence
Sequence
PN Sequence Short
PN Sequence Long
Initial
Value
0x1FE0
0x1FFF
First Three Output Samples
(MSB First) Twos Complement
0x1DF1, 0x3CC8, 0x294E
0x1FE0, 0x2001, 0x1C00
Consult the Memory Map section for information on how to
change these additional digital output timing features through
the SPI.
SDIO/OLM Pin
For applications that do not require SPI mode operation, the
CSB pin is tied to AVDD, and the SDIO/OLM pin controls the
output lane mode according to Table 13.
For applications where this pin is not used, CSB should be
tied to AVDD. When using the one-lane mode, the encode
rate should be ≤62.5 MSPS to meet the maximum output rate
of 1 Gbps.
Table 14. Digital Test Pattern Pin Settings
Selected DTP
Normal Operation
DTP
DTP Voltage
10 kΩ to AGND
AVDD
Resulting
D0±x and D1±x
Normal operation
1000 0000 0000 0000
Additional and custom test patterns can also be observed when
commanded from the SPI port. Consult the Memory Map
section for information about the options available.
CSB Pin
The CSB pin should be tied to AVDD for applications that do
not require SPI mode operation. By tying CSB high, all SCLK
and SDIO information is ignored.
RBIAS Pin
To set the internal core bias current of the ADC, place a
10.0 kΩ, 1% tolerance resistor to ground at the RBIAS pin.
Table 13. Output Lane Mode Pin Settings
OLM Pin
Voltage
AVDD (Default)
GND
and output data. This pin has an internal 10 kΩ resistor to GND.
It can be left unconnected.
OUTPUT TEST MODES
Output Mode
Two-lane. 1× frame, 16-bit serial output
One-lane. 1× frame, 16-bit serial output
SCLK/DTP Pin
The SCLK/DTP pin is for use in applications that do not require
SPI mode operation. This pin can enable a single digital test
pattern if it and the CSB pin are held high during device powerup. When SCLK/DTP is tied to AVDD, the ADC channel
outputs shift out the following pattern: 1000 0000 0000 0000.
The FCO and DCO function normally while all channels shift out
the repeatable test pattern. This pattern allows the user to
perform timing alignment adjustments among the FCO, DCO,
The output test options are described in Table 11 and controlled by
the output test mode bits at Address 0x0D. When an output test
mode is enabled, the analog section of the ADC is disconnected
from the digital back-end blocks and the test pattern is run
through the output formatting block. Some of the test patterns
are subject to output formatting, and some are not. The PN
generators from the PN sequence tests can be reset by setting
Bit 4 or Bit 5 of Register 0x0D. These tests can be performed
with or without an analog signal (if present, the analog signal is
ignored), but they do require an encode clock. For more
information, see the AN-877"QQMJDBUJPO/PUF, Interfacing to
High Speed ADCs via SPI.
Rev. 0 | Page 30 of 40
Data Sheet
AD9253
SERIAL PORT INTERFACE (SPI)
The falling edge of the CSB, in conjunction with the rising edge
of the SCLK, determines the start of the framing. An example of
the serial timing and its definitions can be found in Figure 74
and Table 5.
The AD9253 serial port interface (SPI) allows the user to configure
the converter for specific functions or operations through a
structured register space provided inside the ADC. The SPI
offers the user added flexibility and customization, depending on
the application. Addresses are accessed via the serial port and
can be written to or read from via the port. Memory is organized
into bytes that can be further divided into fields, which are documented in the Memory Map section. For detailed operational
information, see the AN-877 Application Note, Interfacing to
High Speed ADCs via SPI.
Other modes involving the CSB are available. The CSB can be
held low indefinitely, which permanently enables the device;
this is called streaming. The CSB can stall high between bytes to
allow for additional external timing. When CSB is tied high, SPI
functions are placed in high impedance mode. This mode turns
on any SPI pin secondary functions.
During an instruction phase, a 16-bit instruction is transmitted.
Data follows the instruction phase, and its length is determined
by the W0 and W1 bits.
CONFIGURATION USING THE SPI
Three pins define the SPI of this ADC: the SCLK pin, the SDIO
pin, and the CSB pin (see Table 15). The SCLK (a serial clock) is
used to synchronize the read and write data presented from and
to the ADC. The SDIO (serial data input/output) is a dualpurpose pin that allows data to be sent to and read from the
internal ADC memory map registers. The CSB (chip select bar)
is an active low control that enables or disables the read and
write cycles.
In addition to word length, the instruction phase determines
whether the serial frame is a read or write operation, allowing
the serial port to be used both to program the chip and to read
the contents of the on-chip memory. The first bit of the first byte in
a multibyte serial data transfer frame indicates whether a read
command or a write command is issued. If the instruction is a
readback operation, performing a readback causes the serial
data input/output (SDIO) pin to change direction from an input to
an output at the appropriate point in the serial frame.
Table 15. Serial Port Interface Pins
Pin
SCLK
SDIO
CSB
Function
Serial clock. The serial shift clock input, which is used to
synchronize serial interface reads and writes.
Serial data input/output. A dual-purpose pin that
typically serves as an input or an output, depending on
the instruction being sent and the relative position in the
timing frame.
Chip select bar. An active low control that gates the read
and write cycles.
tHIGH
tDS
tS
tDH
All data is composed of 8-bit words. Data can be sent in MSBfirst mode or in LSB-first mode. MSB-first mode is the default
on power-up and can be changed via the SPI port configuration
register. For more information about this and other features,
see the AN-877 Application Note, Interfacing to High Speed
ADCs via SPI.
tCLK
tH
tLOW
CSB
SDIO DON’T CARE
DON’T CARE
R/W
W1
W0
A12
A11
A10
A9
A8
A7
D5
Figure 74. Serial Port Interface Timing Diagram
Rev. 0 | Page 31 of 40
D4
D3
D2
D1
D0
DON’T CARE
10065-078
SCLK DON’T CARE
AD9253
Data Sheet
HARDWARE INTERFACE
The pins described in Table 15 comprise the physical interface
between the user programming device and the serial port of the
AD9253. The SCLK pin and the CSB pin function as inputs
when using the SPI interface. The SDIO pin is bidirectional,
functioning as an input during write phases and as an output
during readback.
The SPI interface is flexible enough to be controlled by either
FPGAs or microcontrollers. One method for SPI configuration
is described in detail in the AN-812 Application Note, Microcontroller-Based Serial Port Interface (SPI) Boot Circuit.
The SPI port should not be active during periods when the full
dynamic performance of the converter is required. Because the
SCLK signal, the CSB signal, and the SDIO signal are typically
asynchronous to the ADC clock, noise from these signals can
degrade converter performance. If the on-board SPI bus is used for
other devices, it may be necessary to provide buffers between
this bus and the AD9253 to prevent these signals from transitioning at the converter inputs during critical sampling periods.
Some pins serve a dual function when the SPI interface is not
being used. When the pins are strapped to DRVDD or ground
during device power-on, they are associated with a specific
function. Table 16 describes the strappable functions supported
on the AD9253.
When the device is in SPI mode, the PDWN pin (if enabled)
remains active. For SPI control of power-down, the PDWN pin
should be set to its default state.
SPI ACCESSIBLE FEATURES
Table 16 provides a brief description of the general features that
are accessible via the SPI. These features are described in detail
in the AN-877 Application Note, Interfacing to High Speed ADCs
via SPI. The AD9253 part-specific features are described in detail
following Table 17, the external memory map register table.
Table 16. Features Accessible Using the SPI
Feature Name
Power Mode
Clock
Offset
Test I/O
Output Mode
Output Phase
ADC Resolution
CONFIGURATION WITHOUT THE SPI
In applications that do not interface to the SPI control registers,
the SDIO/OLM pin, the SCLK/DTP pin, and the PDWN pin
serve as standalone CMOS-compatible control pins. When the
device is powered up, it is assumed that the user intends to use the
pins as static control lines for the duty cycle stabilizer, output
data format, and power-down feature control. In this mode,
CSB should be connected to AVDD, which disables the serial
port interface.
Rev. 0 | Page 32 of 40
Description
Allows the user to set either power-down mode
or standby mode
Allows the user to access the DCS, set the
clock divider, set the clock divider phase, and
enable the sync
Allows the user to digitally adjust the
converter offset
Allows the user to set test modes to have
known data on output bits
Allows the user to set the output mode
Allows the user to set the output clock polarity
Allows for power consumption scaling with
respect to sample rate.
Data Sheet
AD9253
MEMORY MAP
READING THE MEMORY MAP REGISTER TABLE
Default Values
Each row in the memory map register table has eight bit locations.
The memory map is roughly divided into three sections: the chip
configuration registers (Address 0x00 to Address 0x02); the device
index and transfer registers (Address 0x05 and Address 0xFF);
and the global ADC functions registers, including setup, control,
and test (Address 0x08 to Address 0x109).
After the AD9253 is reset, critical registers are loaded with
default values. The default values for the registers are given in
the memory map register table, Table 17.
The memory map register table (see Table 17) lists the default
hexadecimal value for each hexadecimal address shown. The
column with the heading Bit 7 (MSB) is the start of the default
hexadecimal value given. For example, Address 0x05, the device
index register, has a hexadecimal default value of 0x3F. This
means that in Address 0x05, Bits[7:6] = 0, and the remaining
Bits[5:0] = 1. This setting is the default channel index setting.
The default value results in both ADC channels receiving the
next write command. For more information on this function
and others, see the AN-877"QQMJDBUJPO/PUF, Interfacing to
High Speed ADCs via SPI. This application note details the
functions controlled by Register 0x00 to Register 0xFF. The
remaining registers are documented in the Memory Map
Register Descriptions section.
Open Locations
All address and bit locations that are not included in Table 17
are not currently supported for this device. Unused bits of a
valid address location should be written with 0s. Writing to these
locations is required only when part of an address location is
open (for example, Address 0x05). If the entire address location
is open or not listed in Table 17 (for example, Address 0x13), this
address location should not be written.
Logic Levels
An explanation of logic level terminology follows:
•
•
“Bit is set” is synonymous with “bit is set to Logic 1” or
“writing Logic 1 for the bit.”
“Clear a bit” is synonymous with “bit is set to Logic 0” or
“writing Logic 0 for the bit.”
Channel-Specific Registers
Some channel setup functions, such as the signal monitor
thresholds, can be programmed differently for each channel. In
these cases, channel address locations are internally duplicated
for each channel. These registers and bits are designated in
Table 17 as local. These local registers and bits can be accessed
by setting the appropriate data channel bits (A, B, C, or D) and
the clock channel DCO bit (Bit 5) and FCO bit (Bit 4) in
Register 0x05. If all the bits are set, the subsequent write affects
the registers of all channels and the DCO/FCO clock channels.
In a read cycle, only one of the channels (A, B, C, or D) should
be set to read one of the four registers. If all the bits are set
during a SPI read cycle, the part returns the value for Channel
A. Registers and bits designated as global in Table 17 affect the
entire part or the channel features for which independent
settings are not allowed between channels. The settings in
Register 0x05 do not affect the global registers and bits.
Rev. 0 | Page 33 of 40
AD9253
Data Sheet
MEMORY MAP REGISTER TABLE
The AD9253 uses a 3-wire interface and 16-bit addressing and,
therefore, Bit 0 and Bit 7 in Register 0x00 are set to 0, and Bit 3
and Bit 4 are set to 1. When Bit 5 in Register 0x00 is set high,
the SPI enters a soft reset, where all of the user registers revert
to their default values and Bit 2 is automatically cleared.
Table 17.
ADDR
(Hex)
Parameter Name
Chip Configuration Registers
0x00
SPI port
configuration
0x01
Chip ID (global)
0x02
Chip grade
(global)
Bit 7
(MSB)
0=
SDO
active
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
LSB first
Soft
reset
1=
16-bit
address
1=
16-bit
address
Soft
reset
LSB first
Bit 0
(LSB)
0 = SDO
active
8-bit chip ID, Bits[7:0]
AD9253 0x8F = quad 14-bit 80 MSPS/105 MSPS/125 MSPS serial LVDS
Open
Speed grade ID[6:4]
100 = 80 MSPS
101 = 105 MSPS
110 = 125 MSPS
Default
Value
(Hex)
0x18
0x8F
Open
Open
Open
Open
Device Index and Transfer Registers
0x05
Device index
Open
Open
Clock
Channel
DCO
Clock
Channel
FCO
Data
Channel
D
Data
Channel
C
Data
Channel
B
Data
Channel
A
0x3F
0xFF
Open
Open
Open
Open
Open
Open
Open
Initiate
override
0x00
Global ADC Function Registers
0x08
Power modes
Open
(global)
Open
Open
Open
0x09
Open
External
powerdown
pin
function
0 = full
powerdown
1=
standby
Open
Open
Open
Transfer
Clock (global)
Open
Rev. 0 | Page 34 of 40
Open
Open
Power mode
00 = chip run
01 = full powerdown
10 = standby
11 = reset
Open
Duty
cycle
stabilize
0 = off
1 = on
Comments
The nibbles
are mirrored
so that LSBfirst or MSBfirst mode
registers
correctly. The
default for
ADCs is 16-bit
mode.
Unique chip
ID used to
differentiate
devices; read
only.
Unique
speed grade
ID used to
differentiate
graded
devices; read
only.
Bits are set to
determine
which device
on chip
receives the
next write
command.
The default is
all devices on
chip.
Set resolution/
sample rate
override.
0x00
Determines
various
generic
modes of chip
operation.
0x01
Turns duty
cycle stabilizer
on or off.
Data Sheet
ADDR
(Hex)
0x0B
Parameter Name
Clock divide
(global)
0x0C
Enhancement
control
0x0D
Test mode (local
except for PN
sequence resets)
0x10
0x14
Offset adjust
(local)
Output mode
0x15
Output adjust
0x16
Output phase
AD9253
Bit 7
(MSB)
Open
Bit 0
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
(LSB)
Open
Open
Open
Open
Clock divide ratio[2:0]
000 = divide by 1
001 = divide by 2
010 = divide by 3
011 = divide by 4
100 = divide by 5
101 = divide by 6
110 = divide by 7
111 = divide by 8
Open
Open
Open
Open
Open
Chop
Open
Open
mode
0 = off
1 = on
User input test mode
Reset
Reset PN
Output test mode[3:0] (local)
PN long
short
0000 = off (default)
00 = single
gen
gen
0001 = midscale short
01 = alternate
0010 = positive FS
10 = single once
0011 = negative FS
11 = alternate once
0100 = alternating checkerboard
(affects user input test
0101 = PN 23 sequence
mode only,
0110 = PN 9 sequence
Bits[3:0] = 1000)
0111 = one/zero word toggle
1000 = user input
1001 = 1-/0-bit toggle
1010 = 1× sync
1011 = one bit high
1100 = mixed bit frequency
8-bit device offset adjustment [7:0] (local)
Offset adjust in LSBs from +127 to −128 (twos complement format)
Open
Open
Open
Output
Open
Output
Open
LVDS-ANSI/
invert
format
LVDS-IEEE
0=
option
(local)
offset
0 = LVDSbinary
ANSI
1=
1 = LVDStwos
IEEE
complereduced
ment
range link
(global)
(global)
see
Table 18
Open
Open
Output driver
Open
Open
Open
Output
termination[1:0]
drive
0 = 1×
00 = none
drive
01 = 200 Ω
1 = 2×
10 = 100 Ω
drive
11 = 100 Ω
Open
Input clock phase adjust[6:4]
Output clock phase adjust[3:0]
(value is number of input clock
(0000 through 1011)
cycles of phase delay)
see Table 20
see Table 19
Rev. 0 | Page 35 of 40
Default
Value
(Hex)
0x00
Comments
0x00
Enables/
disables chop
mode.
0x00
When set, the
test data is
placed on the
output pins in
place of
normal data.
0x00
Device offset
trim.
Configures
the outputs
and the
format of the
data.
0x01
0x00
Determines
LVDS or other
output
properties.
0x03
On devices
that use
global clock
divide,
determines
which phase
of the divider
output is used
to supply the
output clock.
Internal
latching is
unaffected.
AD9253
ADDR
(Hex)
0x18
Data Sheet
Default
Value
(Hex)
0x04
Bit 7
(MSB)
Open
Bit 6
Open
Bit 5
Open
Bit 4
Open
Bit 3
Open
USER_PATT1_LSB
(global)
USER_PATT1_MSB
(global)
USER_PATT2_LSB
(global)
USER_PATT2_MSB
(global)
Serial output data
control (global)
B7
B6
B5
B4
B3
Bit 0
Bit 2
Bit 1
(LSB)
Internal VREF adjustment
digital scheme[2:0]
000 = 1.0 V p-p
001 = 1.14 V p-p
010 = 1.33 V p-p
011 = 1.6 V p-p
100 = 2.0 V p-p
B2
B1
B0
B15
B14
B13
B12
B11
B10
B9
B8
0x00
B7
B6
B5
B4
B3
B2
B1
B0
0x00
B15
B14
B13
B12
B11
B10
B9
B8
0x00
LVDS
output
LSB
first
Open
Select
2×
frame
0x22
Serial channel
status (local)
Open
SDR/DDR one-lane/two-lane,
bitwise/bytewise[6:4]
000 = SDR two-lane, bitwise
001 = SDR two-lane, bytewise
010 = DDR two-lane, bitwise
011 = DDR two-lane, bytewise
100 = DDR one-lane
Open
Open
Open
Open
Open
0x100
Resolution/
sample rate
override
Open
Resolution/
sample rate
override
enable
0x101
User I/O Control 2
Open
Open
Open
Open
Open
Open
0x102
User I/O Control 3
Open
Open
Open
Open
Open
0x109
Sync
Open
Open
Open
Open
VCM
powerdown
Open
0x19
0x1A
0x1B
0x1C
0x21
Parameter Name
VREF
Resolution
01 = 14 bits
10 = 12 bits
Open
Rev. 0 | Page 36 of 40
Open
Serial output
number of bits
00 = 16 bits
10 = 12 bits
Channel
output
reset
Channel
powerdown
Sample rate
000 = 20 MSPS
001 = 40 MSPS
010 = 50 MSPS
011 = 65 MSPS
100 = 80 MSPS
101 = 105 MSPS
110 = 125 MSPS
Open
SDIO
pulldown
Open
Open
Sync
next
only
Enable
sync
0x00
0x30
0x00
0x00
Comments
Selects and/or
adjusts the
VREF.
User Defined
Pattern 1 LSB.
User Defined
Pattern 1 MSB.
User Defined
Pattern 2 LSB.
User Defined
Pattern 2 MSB.
Serial stream
control.
Default causes
MSB first and
the native bit
stream.
Used to power
down
individual
sections of a
converter.
Resolution/
sample rate
override
(requires
transfer
register, 0xFF).
0x00
Disables SDIO
pull-down.
0x00
VCM control.
0x00
Data Sheet
AD9253
MEMORY MAP REGISTER DESCRIPTIONS
For additional information about functions controlled in
Register 0x00 to Register 0xFF, see the AN-877 Application Note,
Interfacing to High Speed ADCs via SPI.
Device Index (Register 0x05)
There are certain features in the map that can be set independently for each channel, whereas other features apply
globally to all channels (depending on context) regardless of
which are selected. The first four bits in Register 0x05 can be
used to select which individual data channels are affected. The
output clock channels can be selected in Register 0x05 as well. A
smaller subset of the independent feature list can be applied to
those devices.
Output Mode (Register 0x14)
Bit 7—Open
Bit 6—LVDS-ANSI/LVDS-IEEE Option
Setting this bit chooses LVDS-IEEE (reduced range) option.
The default setting is LVDS-ANSI. As described in Table 18,
when LVDS-ANSI or LVDS-IEEE reduced range link is selected,
the user can select the driver termination. The driver current
is automatically selected to give the proper output swing.
Table 18. LVDS-ANSI/LVDS-IEEE Options
Output
Mode,
Bit 6
0
Output
Mode
LVDS-ANSI
Transfer (Register 0xFF)
All registers except Register 0x100 are updated the moment
they are written. Setting Bit 0 of this transfer register high
initializes the settings in the ADC sample rate override register
(Address 0x100).
Power Modes (Register 0x08)
Bits[7:6]—Open
1
LVDS-IEEE
reduced
range link
Output
Driver
Termination
User
selectable
User
selectable
Output Driver
Current
Automatically
selected to give
proper swing
Automatically
selected to give
proper swing
Bits[5:3]—Open
Bit 2—Output Invert
Setting this bit inverts the output bit stream.
Bit 5—External Power-Down Pin Function
If set, the external PDWN pin initiates power-down mode. If
cleared, the external PDWN pin initiates standby mode.
Bit 1—Open
Bit 0—Output Format
By default, this bit is set to send the data output in twos
complement format. Resetting this bit changes the output mode
to offset binary.
Bits[4:2]—Open
Bits[1:0]—Power Mode
In normal operation (Bits[1:0] = 00), all ADC channels are
active.
Output Adjust (Register 0x15)
Bits[7:6]—Open
In power-down mode (Bits[1:0] = 01), the digital datapath clocks
are disabled while the digital datapath is reset. Outputs are
disabled.
In standby mode (Bits[1:0] = 10), the digital datapath clocks
and the outputs are disabled.
Bits[5:4]—Output Driver Termination
These bits allow the user to select the internal termination
resistor.
Bits[3:1]—Open
During a digital reset (Bits[1:0] = 11), all the digital datapath
clocks and the outputs (where applicable) on the chip are reset,
except the SPI port. Note that the SPI is always left under
control of the user; that is, it is never automatically disabled or
in reset (except by power-on reset).
Enhancement Control (Register 0x0C)
Bits[7:3]—Open
Bit 2—Chop Mode
For applications that are sensitive to offset voltages and other
low frequency noise, such as homodyne or direct conversion
receivers, chopping in the first stage of the AD9253 is a feature
that can be enabled by setting Bit 2. In the frequency domain,
chopping translates offsets and other low frequency noise to
fCLK/2 where it can be filtered.
Bit 0—Output Drive
Bit 0 of the output adjust register controls the drive strength on
the LVDS driver of the FCO and DCO outputs only. The default
values set the drive to 1× while the drive can be increased to 2×
by setting the appropriate channel bit in Register 0x05 and then
setting Bit 0. These features cannot be used with the output
driver termination select. The termination selection takes
precedence over the 2× driver strength on FCO and DCO when
both the output driver termination and output drive are selected.
Output Phase (Register 0x16)
Bit 7—Open
Bits[6:4]—Input Clock Phase Adjust
Bits[1:0]—Open
Rev. 0 | Page 37 of 40
AD9253
Data Sheet
Table 19. Input Clock Phase Adjust Options
Serial Output Data Control (Register 0x21)
Input Clock Phase
Adjust, Bits[6:4]
000 (Default)
001
010
011
100
101
110
111
The serial output data control register is used to program the
AD9253 in various output data modes depending upon the data
capture solution. Table 21 describes the various serialization
options available in the AD9253.
Number of Input Clock Cycles of
Phase Delay
0
1
2
3
4
5
6
7
This register is designed to allow the user to downgrade the device.
Any attempt to upgrade the default speed grade results in a chip
power-down. Settings in this register are not initialized until Bit 0
of the transfer register (Register 0xFF) is written high.
User I/O Control 2 (Register 0x101)
Bits[7:1]—Open
Bits[3:0]—Output Clock Phase Adjust
Table 20. Output Clock Phase Adjust Options
Output Clock (DCO),
Phase Adjust, Bits[3:0]
0000
0001
0010
0011 (Default)
0100
0101
0110
0111
1000
1001
1010
1011
Resolution/Sample Rate Override (Register 0x100)
DCO Phase Adjustment (Degrees
Relative to D0±x/D1±x Edge)
0
60
120
180
240
300
360
420
480
540
600
660
Bit 0—SDIO Pull-Down
Bit 0 can be set to disable the internal 30 kΩ pull-down on the
SDIO pin, which can be used to limit the loading when many
devices are connected to the SPI bus.
User I/O Control 3 (Register 0x102)
Bits[7:4]—Open
Bit 3—VCM Power-Down
Bit 3 can be set high to power down the internal VCM
generator. This feature is used when applying an external
reference.
Bits[2:0]—Open
Table 21. SPI Register Options
Register 0x21
Contents
0x30
0x20
0x10
0x00
0x34
0x24
0x14
0x04
0x40
0x32
0x22
0x12
0x02
0x36
0x26
0x16
0x06
0x42
Serialization Options Selected
Serial Output Number
of Bits (SONB)
Frame Mode
Serial Data Mode
16-bit
1×
DDR two-lane bytewise
16-bit
1×
DDR two-lane bitwise
16-bit
1×
SDR two-lane bytewise
16-bit
1×
SDR two-lane bitwise
16-bit
2×
DDR two-lane bytewise
16-bit
2×
DDR two-lane bitwise
16-bit
2×
SDR two-lane bytewise
16-bit
2×
SDR two-lane bitwise
16-bit
1×
DDR one-lane
12-bit
1×
DDR two-lane bytewise
12-bit
1×
DDR two-lane bitwise
12-bit
1×
SDR two-lane bytewise
12-bit
1×
SDR two-lane bitwise
12-bit
2×
DDR two-lane bytewise
12-bit
2×
DDR two-lane bitwise
12-bit
2×
SDR two-lane bytewise
12-bit
2×
SDR two-lane bitwise
12-bit
1×
DDR one-lane
Rev. 0 | Page 38 of 40
DCO Multiplier
4 × fS
4 × fS
8 × fS
8 × fS
4 × fS
4 × fS
8 × fS
8 × fS
8 × fS
3 × fS
3 × fS
6 × fS
6 × fS
3 × fS
3 × fS
6 × fS
6 × fS
6 × fS
Timing Diagram
Figure 2 (default setting)
Figure 2
Figure 2
Figure 2
Figure 4
Figure 4
Figure 4
Figure 4
Figure 6
Figure 3
Figure 3
Figure 3
Figure 3
Figure 5
Figure 5
Figure 5
Figure 5
Figure 7
Data Sheet
AD9253
APPLICATIONS INFORMATION
DESIGN GUIDELINES
VCM
Before starting design and layout of the AD9253 as a system,
it is recommended that the designer become familiar with these
guidelines, which describes the special circuit connections and
layout requirements that are needed for certain pins.
The VCM pin should be decoupled to ground with a 0.1 μF
capacitor.
When connecting power to the AD9253, it is recommended
that two separate 1.8 V supplies be used. Use one supply for
analog (AVDD); use a separate supply for the digital outputs
(DRVDD). For both AVDD and DRVDD, several different
decoupling capacitors should be used to cover both high and
low frequencies. Place these capacitors close to the point of
entry at the PCB level and close to the pins of the part, with
minimal trace length.
A single PCB ground plane should be sufficient when using the
AD9253. With proper decoupling and smart partitioning of the
PCB analog, digital, and clock sections, optimum performance
is easily achieved.
EXPOSED PAD THERMAL HEAT SLUG
RECOMMENDATIONS
It is required that the exposed pad on the underside of the ADC
be connected to analog ground (AGND) to achieve the best
electrical and thermal performance of the AD9253. An exposed
continuous copper plane on the PCB should mate to the
AD9253 exposed pad, Pin 0. The copper plane should have
several vias to achieve the lowest possible resistive thermal path
for heat dissipation to flow through the bottom of the PCB.
These vias should be solder-filled or plugged.
To maximize the coverage and adhesion between the ADC and
PCB, partition the continuous copper plane by overlaying a
silkscreen on the PCB into several uniform sections. This provides
several tie points between the ADC and PCB during the reflow
process, whereas using one continuous plane with no partitions
only guarantees one tie point. See Figure 75 for a PCB layout
example. For detailed information on packaging and the PCB
layout of chip scale packages, see the AN-772"QQMJDBUJPO/PUF,
A Design and Manufacturing Guide for the Lead Frame Chip
Scale Package (LFCSP), at www.analog.com.
The VREF pin should be externally decoupled to ground with a
low ESR, 1.0 μF capacitor in parallel with a low ESR, 0.1 μF
ceramic capacitor.
SPI PORT
The SPI port should not be active during periods when the full
dynamic performance of the converter is required. Because the
SCLK, CSB, and SDIO signals are typically asynchronous to the
ADC clock, noise from these signals can degrade converter
performance. If the on-board SPI bus is used for other devices,
it may be necessary to provide buffers between this bus and the
AD9253 to keep these signals from transitioning at the converter inputs during critical sampling periods.
CROSSTALK PERFORMANCE
The AD9253 is available in a 48-lead LFCSP package with the
input pairs on either corner of the chip. See Figure 9 for the pin
configuration. To maximize the crosstalk performance on the
board, add grounded filled vias in between the adjacent
channels as shown in Figure 76.
VIN
CHANNEL A
GROUNDED
FILLED VIAS
FOR ADDED
CROSSTALK
ISOLATION
10065-080
SILKSCREEN PARTITION
PIN 1 INDICATOR
Figure 75. Typical PCB Layout
Rev. 0 | Page 39 of 40
VIN
CHANNEL B
VIN
CHANNEL D
PIN 1
VIN
CHANNEL C
Figure 76. Layout Technique to Maximize Crosstalk Performance
10065-088
POWER AND GROUND RECOMMENDATIONS
REFERENCE DECOUPLING
AD9253
Data Sheet
OUTLINE DIMENSIONS
0.30
0.23
0.18
PIN 1
INDICATOR
37
36
48
1
0.50
BSC
TOP VIEW
0.80
0.75
0.70
0.45
0.40
0.35
EXPOSED
PAD
24
SEATING
PLANE
5.65
5.60 SQ
5.55
13
BOTTOM VIEW
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
PIN 1
INDICATOR
0.20 MIN
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
COMPLIANT TO JEDEC STANDARDS MO-220-WKKD.
02-14-2011-B
7.10
7.00 SQ
6.90
Figure 77. 48-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
7 mm × 7 mm Body, Very Very Thin Quad
(CP-48-13)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
AD9253BCPZ-80
AD9253BCPZRL7-80
AD9253BCPZ-105
AD9253BCPZRL7-105
AD9253BCPZ-125
AD9253BCPZRL7-125
AD9253-125EBZ
1
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
48-Lead Lead Frame Chip Scale Package (LFCSP_WQ)
48-Lead Lead Frame Chip Scale Package (LFCSP_WQ)
48-Lead Lead Frame Chip Scale Package (LFCSP_WQ)
48-Lead Lead Frame Chip Scale Package (LFCSP_WQ)
48-Lead Lead Frame Chip Scale Package (LFCSP_WQ)
48-Lead Lead Frame Chip Scale Package (LFCSP_WQ)
Evaluation Board
Z = RoHS Compliant Part.
©2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D10065-0-10/11(0)
Rev. 0 | Page 40 of 40
Package Option
CP-48-13
CP-48-13
CP-48-13
CP-48-13
CP-48-13
CP-48-13