AD9272 Datasheet, PDF (1/2 Pages) Analog Devices – Octal LNA/VGA/AAF/ADC and Crosspoint Switch

Octal LNA/VGA/AAF/ADC
and Crosspoint Switch
AD9272
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; VIN 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
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-to-
digital 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.
FUNCTIONAL BLOCK DIAGRAM
LOSW-A
LO-A
LI-A
LNA
VGA
LG-A
LOSW-B
LO-B
LI-B
LG-B
LNA
VGA
LOSW-C
LO-C
LI-C
LG-C
LNA
VGA
LOSW-D
LO-D
LI-D
LNA
VGA
LG-D
LOSW-E
LO-E
LI-E
LG-E
LNA
VGA
LOSW-F
LO-F
LI-F
LG-F
LNA
VGA
LOSW-G
LO-G
LI-G
LNA
VGA
LG-G
LOSW-H
LO-H
LI-H
LG-H
LNA
VGA
SWITCH
ARRAY
AD9272
AAF
12-BIT
ADC
SERIAL
LVDS
DOUTA+
DOUTA–
AAF
12-BIT
ADC
SERIAL
LVDS
DOUTB+
DOUTB–
AAF
12-BIT
ADC
SERIAL
LVDS
DOUTC+
DOUTC–
AAF
12-BIT
ADC
SERIAL
LVDS
DOUTD+
DOUTD–
AAF
12-BIT
ADC
SERIAL
LVDS
DOUTE+
DOUTE–
AAF
12-BIT
ADC
SERIAL
LVDS
DOUTF+
DOUTF–
AAF
12-BIT
ADC
SERIAL
LVDS
DOUTG+
DOUTG–
AAF
12-BIT
ADC
REFERENCE
SERIAL
LVDS
DOUTH+
DOUTH–
FCO+
FCO–
DCO+
DCO–
Figure 1.
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.
For more information about the AD9272, contact Analog Devices, Inc., at [e-mail].
Rev. Sp0
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