ANALOG DEVICES AD9272 Service Manual

Octal LNA/VGA/AAF/ADC

www.BDTIC.com/ADI

and Crosspoint Switch

FEATURES

8 channels of LNA, VGA, AAF, and ADC Low noise preamplifier (LNA)

Input-referred noise voltage = 0.75 nV/√Hz

(gain = 21.3 dB) @ 5 MHz typical SPI-programmable gain = 15.6 dB/17.9 dB/21.3 dB Single-ended input; V

maximum = 733 mV p-p/

550 mV p-p/367 mV p-p Dual-mode active input impedance matching Bandwidth (BW) > 100 MHz Full-scale (FS) output = 4.4 V p-p differential

Variable gain amplifier (VGA)

Attenuator range = −42 dB to 0 dB SPI-programmable PGA gain = 21 dB/24 dB/27 dB/30 dB Linear-in-dB gain control

Antialiasing filter (AAF)

Programmable 2nd-order low-pass filter (LPF) from

8 MHz to 18 MHz Programmable high-pass filter (HPF)

Analog-to-digital converter (ADC)

12 bits at 10 MSPS to 80 MSPS SNR = 70 dB SFDR = 75 dB Serial LVDS (ANSI-644, IEEE 1596.3 reduced range link) Data and frame clock outputs

Includes an 8 × 8 differential crosspoint switch to support

continuous wave (CW) Doppler

Low power, 195 mW per channel at 12 bits/40 MSPS (TGC) 120 mW per channel in CW Doppler

LOSW-A

LO-A

LI-A

LG-A

LOSW-B

LO-B

LI-B

LG-B

LOSW-C

LO-C

LI-C

LG-C

LOSW-D

LO-D

LI-D

LG-D

LOSW-E

LO-E

LI-E

LG-E

LOSW-F

LO-F

LI-F

LG-F

LOSW-G

LO-G

LI-G

LG-G

LOSW-H

LO-H

LI-H

LG-H

Flexible power-down modes Overload recovery in <10 ns Fast recovery from low power standby mode, <2 μs 100-lead TQFP

APPLICATIONS

Medical imaging/ultrasound Automotive radar

GENERAL DESCRIPTION

The AD9272 is designed for low cost, low power, small size, and ease of use. It contains eight channels of a low noise preamplifier (LNA) with a variable gain amplifier (VGA); an antialiasing filter (AAF); and a 12-bit, 10 MSPS to 80 MSPS analog-todigital converter (ADC).

Each channel features a variable gain range of 42 dB, a fully differential signal path, an active input preamplifier termination, a maximum gain of up to 52 dB, and an ADC with a conversion rate of up to 80 MSPS. The channel is optimized for dynamic performance and low power in applications where a small package size is critical.

For more information about the AD9272, contact Analog Devices, Inc., at highspeed.converters@analog.com.

Rev. Sp0

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.

The LNA has a single-ended-to-differential gain that is selectable through the SPI. The LNA input-referred noise voltage is typically

0.75 nV/√Hz at a gain of 21.3 dB, and the combined input-referred noise voltage of the entire channel is 0.85 nV/√Hz at maximum gain. Assuming a 15 MHz noise bandwidth (NBW) and a 21.3 dB LNA gain, the input SNR is about 92 dB. In CW Doppler mode, the LNA output drives a transconductance amp that is switched through an 8 × 8 differential crosspoint switch. The switch is programmable through the SPI.

FUNCTIONAL BLOCK DIAGRAM

AVDD1

AVDD2

LNA

SWITCH

ARRAY

AND

CWD[7:0]+

VGA

CWD[7:0]–

AAF

REFERENCE

GAIN–

GAIN+

Figure 1.

PDWN

VREF

STBY

RBIAS

AD9272

12-BIT

ADC

12-BIT

ADC

12-BIT

ADC

12-BIT

ADC

12-BIT

ADC

12-BIT

ADC

12-BIT

ADC

12-BIT

ADC

SERIAL

CSB

AD9272

DRVDD

SERIAL

LVDS

SERIAL

LVDS

SERIAL

LVDS

SERIAL

LVDS

SERIAL

LVDS

SERIAL

LVDS

SERIAL

LVDS

SERIAL

LVDS

RATE

PORT

DATA

INTERFACE

MULTIPLIER

SDIO

CLK–

CLK+

SCLK

DOUTA+ DOUTA–

DOUTB+ DOUTB–

DOUTC+ DOUTC–

DOUTD+ DOUTD–

DOUTE+ DOUTE–

DOUTF+ DOUTF–

DOUTG+ DOUTG–

DOUTH+ DOUTH–

FCO+ FCO–

DCO+ DCO–

07029-001

AD9272

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NOTES

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