Octal Ultrasound AFE with Digital Demodulator AD9674 Data Sheet FEATURES GENERAL DESCRIPTION 8 channels of LNA, VGA, AAF, ADC, and digital RF decimator Low power: 150 mW per channel, TGC mode, 40 MSPS; 65 mW per channel, CW mode; <30 mW at power-up Time gain compensation (TGC) channel input-referred noise: 0.8 nV/√Hz, maximum gain Flexible power-down modes Fast recovery from low power standby mode: <2 μs Low noise preamplifier (LNA) Input-referred noise voltage: 0.78 nV/√Hz, gain = 21.6 dB Programmable gain: 15.6 dB/17.9 dB/21.6 dB 0.1 dB compression: 1.00 V p-p/0.75 V p-p/0.45 V p-p Flexible active input impedance matching Variable gain amplifier (VGA) Attenuator range: 45 dB, linear-in-dB gain control Postamp 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) Analog-to-digital converter (ADC) Signal-to-noise ratio (SNR): 75 dB, 14 bits up to 125 MSPS Configurable serial low voltage differential signaling (LVDS) Continuous wave (CW) doppler 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 RF digital HPF and decimation by 2 10 mm × 10 mm, 144-ball CSP_BGA The AD9674 is designed for low cost, low power, small size, and ease of use for medical ultrasound. 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, a digital HPF, and RF decimation by 2. 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. 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 serial port interface. This product is protected by a U.S. patent. FUNCTIONAL BLOCK DIAGRAM AVDD1 AVDD2 LO-A TO LO-H DVDD PDWN STBY DRVDD CWQ+ CWQ– CWI+ CWI– CWD I/Q DEMODULATOR LOSW-A TO LOSW-H LI-A TO LI-H LNA LG-A TO LG-H VGA 14-BIT ADC AAF FILTER/ DECIMATOR SERIALIZER LVDS DOUTA+ TO DOUTH+ DOUTA– TO DOUTH– AD9674 8 CHANNELS 11293-001 FCO+ FCO– DCO+ DCO– CLK– DATA RATE MULTIPLIER CLK+ SDIO CSB SCLK GPO[0:3] TX_TRIG– ADDR[0:4] SERIAL PORT INTERFACE NCO TX_TRIG+ VREF RBIAS REFERENCE GAIN+ GAIN– MLO– MLO+ RESET– RESET+ LO GENERATION Figure 1. For more information about the AD9674, contact Analog Devices, Inc., at [email protected]. Rev. Sp0 Document Feedback 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. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 ©2013 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com Data Sheet AD9674 NOTES ©2013 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D11293F-0-4/13(Sp0) Rev. Sp0 | Page 2 of 2