JESD204B Octal Ultrasound AFE with
Digital Demodulator
Data Sheet
AD9671
FEATURES
GENERAL DESCRIPTION
8 channels of LNA, VGA, AAF, ADC, and digital demodulator/
decimator
Low power: 150 mW per channel, time gain compensation
(TGC) mode, 40 MSPS
62.5 mW per channel, continuous wave (CW) mode;
<30 mW in power-down mode
10 mm × 10 mm, 144-ball CSP_BGA
TGC channel input referred noise: 0.82 nV/√Hz,
maximum gain
Flexible power-down modes
Fast recovery from low power standby mode: <2 μs
Low noise preamplifier (LNA)
Input referred noise: 0.78 nV/√Hz, gain = 21.6 dB
Programmable gain: 15.6 dB/17.9 dB/21.6 dB
0.1 dB compression: 1000 mV p-p/750 mV p-p/450 mV p-p
Flexible active input impedance matching
Variable gain amplifier (VGA)
The AD9671 is designed for low cost, low power, small size, and
ease of use for medical ultrasound applications. It contains eight
channels of a VGA with an LNA, a CW harmonic rejection I/Q
demodulator with programmable phase rotation, an AAF, an
ADC, and a digital demodulator and decimator for data
processing and bandwidth reduction.
Each channel features a maximum gain of up to 52 dB, a fully
differential signal path, and an active input preamplifier termination.
The channel is optimized for high dynamic performance and
low power in applications where a small package size is critical.
The LNA has a single-ended to differential gain that is selectable
through the serial port interface (SPI). Assuming a 15 MHz noise
bandwidth (NBW) and a 21.6 dB LNA gain, the LNA input SNR
is 94 dB. In CW Doppler mode, each LNA output drives an I/Q
demodulator that has independently programmable phase
rotation with 16 phase settings.
Attenuator range: 45 dB, linear-in-dB gain control
Postamplifier (PGA) gain: 21 dB/24 dB/27 dB/30 dB
Antialiasing filter (AAF)
Programmable, second-order low-pass filter (LPF) from
8 MHz to 18 MHz or 13.5 MHz to 30 MHz and high-pass
filter (HPF)
Power-down of individual channels is supported to increase
battery life for portable applications. Standby mode allows quick
power-up for power cycling. In CW Doppler operation, the
VGA, AAF, and ADC are powered down. The ADC contains
several features designed to maximize flexibility and minimize
system cost, such as a programmable clock, data alignment, and
programmable digital test pattern generation. The digital test
patterns include built-in fixed patterns, built-in pseudorandom
patterns, and custom user defined test patterns entered via the SPI.
Analog-to-digital converter (ADC)
Signal-to-noise ratio (SNR): 75 dB, 14 bits up to 125 MSPS
JESD204B Subclass 0 coded serial digital outputs
CW Doppler (CWD) mode harmonic rejection I/Q demodulator
Individual programmable phase rotation
Dynamic range per channel: 160 dBFS/√Hz
Close-in SNR: 156 dBc/√Hz, 1 kHz offset, −3 dBFS input
Digital demodulator/decimator
I/Q demodulator with programmable oscillator
APPLICATIONS
Medical imaging/ultrasound
Nondestructive testing (NDT)
Rev. A
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