14-Bit, 1.25 GSPS JESD204B,
Dual Analog-to-Digital Converter
AD9691
Data Sheet
FEATURES
FUNCTIONAL BLOCK DIAGRAM
AVDD1 AVDD2 AVDD3 AVDD_SR DVDD DRVDD
SPIVDD
JESD204B (Subclass 1) coded serial digital outputs
1.9 W total power per channel (default settings)
SFDR = 77 dBFS at 340 MHz
SNR = 63.4 dBFS at 340 MHz (AIN = −1.0 dBFS)
Noise density = −152.6 dBFS/Hz
1.25 V, 2.50 V, and 3.3 V dc supply operation
No missing codes
1.58 V p-p differential full scale input voltage
Flexible termination impedance
(1.25V) (2.50V) (3.3V)
(1.25V)
(1.25V) (1.25V) (1.8V TO 3.3V)
BUFFER
VIN+A
VIN–A
ADC
14
CORE
DIGITAL
SERDOUT0±
SERDOUT1±
SERDOUT2±
SERDOUT3±
SERDOUT4±
SERDOUT5±
SERDOUT6±
SERDOUT7±
DOWN-
CONVERTER
8
FD_A
SIGNAL
MONITOR
DIGITAL
DOWN-
CONVERTER
FD_B
14
VIN+B
VIN–B
ADC
CORE
CONTROL
REGISTERS
BUFFER
FAST
DETECT
V_1P0
400 Ω, 200 Ω, 100 Ω, and 50 Ω differential
1.5 GHz usable analog input full power bandwidth
95 dB channel isolation/crosstalk
Amplitude detection bits for efficient AGC implementation
2 integrated wideband digital processors per channel
12-bit NCO, up to 4 cascaded half-band filters
Integer clock divide by 1, 2, 4, or 8
AD9691
SIGNAL
SYNCINB±
SYSREF±
JESD204B
SUBCLASS 1
CONTROL
MONITOR
CLOCK
GENERATION
CLK+
CLK–
SPI CONTROL
÷2
÷4
÷8
PDWN/
STBY
AGND DRGND DGND
SDIO SCLK CSB
Figure 1.
Flexible JESD204B lane configurations
Timestamp feature
Small signal dither
APPLICATIONS
Communications (wideband receivers and digital predistortion)
Instrumentation (spectrum analyzers, network analyzers,
integrated RF test solutions)
DOCSIS 3.x CMTS upstream receive paths
High speed data acquisition systems
this threshold indicator has low latency, the user can quickly
turn down the system gain to avoid an overrange condition at
the ADC input.
Users can configure the Subclass 1 JESD204B-based high speed
serialized output in a variety of one-, two-, four- or eight-lane
configurations, depending on the DDC configuration and the
acceptable lane rate of the receiving logic device. Multiple device
synchronization is supported through the SYSREF input pins.
GENERAL DESCRIPTION
The AD9691 is a dual, 14-bit, 1.25 GSPS analog-to-digital converter
(ADC). The device has an on-chip buffer and sample-and-hold
circuit designed for low power, small size, and ease of use. The
device is designed for sampling wide bandwidth analog signals
of up to 1.5 GHz.
The AD9691 is available in a Pb-free, 88-lead LFCSP and is
specified over the −40°C to +85°C industrial temperature range.
This product is protected by a U.S. patent.
The dual ADC cores feature a multistage, differential pipelined
architecture with integrated output error correction logic. Each
ADC features wide bandwidth inputs supporting a variety of
user-selectable input ranges. An integrated voltage reference
eases design considerations.
PRODUCT HIGHLIGHTS
1. Low power consumption analog core, 14-bit, 1.25 GSPS
dual ADC with 1.9 W per channel.
2. Wide full power bandwidth supports intermediate
frequency (IF) sampling of signals up to 1.5 GHz.
3. Buffered inputs with programmable input termination
eases filter design and implementation.
4. Flexible serial port interface (SPI) controls various product
features and functions to meet specific system requirements.
5. Programmable fast overrange detection.
Each ADC data output is internally connected to two digital
downconverters (DDCs). Each DDC consists of four cascaded
signal processing stages: a 12-bit frequency translator (NCO)
and four half-band decimation filters.
In addition to the DDC blocks, the AD9691 has a programmable
threshold detector that allows monitoring of the incoming
signal power using the fast detect output bits of the ADC. Because
6. 12 mm × 12 mm, 88-lead LFCSP.
Rev. 0
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