16-Bit, 80 MSPS/105 MSPS/125 MSPS, 1.8 V Dual
Analog-to-Digital Converter (ADC)
AD9268
FUNCTIONAL BLOCK DIAGRAM
FEATURES
SDIO/ SCLK/
SNR = 78.2 dBFS @ 70 MHz and 125 MSPS
SFDR = 88 dBc @ 70 MHz and 125 MSPS
Low power: 750 mW @ 125 MSPS
AVDD
CSB
DRVDD
DCS
DFS
SPI
AD9268
1.8 V analog supply operation
ORA
1.8 V CMOS or LVDS output supply
Integer 1-to-8 input clock divider
IF sampling frequencies to 300 MHz
−153.6 dBm/Hz small-signal input noise with 200 Ω input
impedance @ 70 MHz and 125 MSPS
Optional on-chip dither
Programmable internal ADC voltage reference
Integrated ADC sample-and-hold inputs
Flexible analog input range: 1 V p-p to 2 V p-p
Differential analog inputs with 650 MHz bandwidth
ADC clock duty cycle stabilizer
PROGRAMMING DATA
CMOS/LVDS
D15A (MSB)
TO
D0A (LSB)
VIN+A
VIN–A
16
ADC
OUTPUT BUFFER
CLK+
CLK–
DIVIDE 1
TO 8
VREF
SENSE
DCOA
DCOB
DUTY CYCLE
STABILIZER
DCO
GENERATION
REF
SELECT
VCM
RBIAS
VIN–B
VIN+B
ORB
D15B (MSB)
TO
D0B (LSB)
16
CMOS/LVDS
OUTPUT BUFFER
ADC
95 dB channel isolation/crosstalk
Serial port control
MULTICHIP
SYNC
User-configurable, built-in self-test (BIST) capability
Energy-saving power-down modes
AGND
SYNC
PDWN
OEB
NOTES
1. PIN NAMES ARE FOR THE CMOS PIN CONFIGURATION ONLY;
SEE FIGURE 7 FORLVDS PIN NAMES.
APPLICATIONS
Figure 1.
Communications
Diversity radio systems
PRODUCT HIGHLIGHTS
Multimode digital receivers (3G)
GSM, EDGE, W-CDMA, LTE,
CDMA2000, WiMAX, TD-SCDMA
I/Q demodulation systems
Smart antenna systems
General-purpose software radios
Broadband data applications
Ultrasound equipment
1. On-chip dither option for improved SFDR performance
with low power analog input.
2. Proprietary differential input that maintains excellent SNR
performance for input frequencies up to 300 MHz.
3. Operation from a single 1.8 V supply and a separate digital
output driver supply accommodating 1.8 V CMOS or
LVDS outputs.
4. Standard serial port interface (SPI) that supports various
product features and functions, such as data formatting
(offset binary, twos complement, or gray coding), enabling
the clock DCS, power-down, test modes, and voltage
reference mode.
5. Pin compatibility with the AD9258, allowing a simple
migration from 16 bits to 14 bits. The AD9268 is also pin
compatible with the AD9251, AD9231, and AD9204 family
of products for lower sample rate, low power applications.
Rev. A
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