AD6641 Datasheet, PDF (1/28 Pages) Analog Devices – 250 MHz Bandwidth DPD Observation Receiver

250 MHz Bandwidth
DPD Observation Receiver
AD6641
FEATURES
SNR = 65.8 dBFS at fIN up to 250 MHz at 500 MSPS
ENOB of 10.5 bits at fIN up to 250 MHz at 500 MSPS (−1.0 dBFS)
SFDR = 80 dBc at fIN up to 250 MHz at 500 MSPS (−1.0 dBFS)
Excellent linearity
DNL = ±0.5 LSB typical, INL = ±0.6 LSB typical
Integrated 16k × 12 FIFO
FIFO readback options
12-bit parallel CMOS at 62.5 MHz
6-bit DDR LVDS interface
SPORT at 62.5 MHz
SPI at 25 MHz
High speed synchronization capability
1 GHz full power analog bandwidth
Integrated input buffer
On-chip reference, no external decoupling required
Low power dissipation
695 mW at 500 MSPS
Programmable input voltage range
1.18 V to 1.6 V, 1.5 V nominal
1.9 V analog and digital supply operation
1.9 V or 3.3 V SPI and SPORT operation
Clock duty cycle stabilizer
Integrated data clock output with programmable clock and
data alignment
GENERAL DESCRIPTION
The AD6641 is a 250 MHz bandwidth digital predistortion
(DPD) observation receiver that integrates a 12-bit 500 MSPS
ADC, a 16k × 12 FIFO, and a multimode back end that allows
users to retrieve the data through a serial port (SPORT), the SPI
interface, a 12-bit parallel CMOS port, or a 6-bit DDR LVDS
port after being stored in the integrated FIFO memory. It is opti-
mized for outstanding dynamic performance and low power
consumption and is suitable for use in telecommunications
applications such as a digital predistortion observation path
where wider bandwidths are desired. All necessary functions,
including the sample-and-hold and voltage reference, are
included on the chip to provide a complete signal conversion
solution.
The on-chip FIFO allows small snapshots of time to be captured
via the ADC and read back at a lower rate. This reduces the
constraints of signal processing by transferring the captured
data at an arbitrary time and at a much lower sample rate. The
FIFO can be operated in several user-programmable modes. In
the single capture mode, the ADC data is captured when sig-
naled via the SPI port or the use of the external FILL± pins. In
the continuous capture mode, the data is loaded continuously
into the FIFO and the FILL± pins are used to stop this operation.
APPLICATIONS
Wireless and wired broadband communications
Communications test equipment
Power amplifier linearization
FUNCTIONAL BLOCK DIAGRAM
FILL+ FILL– DUMP
CLK+
CLK–
VIN+
VIN–
CLOCK AND CONTROL
ADC
FIFO
16k × 12
PARALLEL
AND
SPORT
OUTPUTS
PCLK+
PCLK–
PD[5:0]± IN DDR LVDS MODE
OR PD[11:0] IN CMOS MODE
SP_SCLK
SP_SDFS
SP_SDO
SPI CONTROL
REFERENCE _{AND DATA}
VREF SCLK, SDIO, AND CSB
Figure 1.
FULL
EMPTY
Rev. 0
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