AD9670Supports medical ultrasound applications designed for low cost, low power, small size, and ease of use. It contains 8 channels of variable gain amplifier (VGA), low noise preamplifier (LNA), CW harmonic suppression I/Q demodulator with programmable phase rotation, antialiasing filter (AAF),
Analog-to-digital converters(ADC) and digital demodulators and decimators for processing data and reducing bandwidth.
Each channel has a maximum gain of 52 dB, a fully differential signal path, and an active input preamplifier termination. Channels are optimized for high dynamic range and low power consumption for applications requiring a small package size.
The LNA has single-ended-to-differential gain and can be selected via SPI. Assuming a noise bandwidth (NBW) of 15 MHz and an LNA gain of 21.6 dB, the LNA input signal-to-noise ratio (SNR) is 94 dB. In CW Doppler mode, each LNA output drives an I/Q demodulator. Each demodulator has independently programmable phase rotation and 16 phase settings.
Each channel can be individually entered into power-down mode, extending battery life in portable applications. Standby mode allows quick power-up for power-on. When operating in CW Doppler mode, the VGA, AAF, and ADC all enter power-down mode. Built-in features such as programmable clocks, data alignment, and programmable digital test code generation allow for optimal device flexibility and minimal system cost. Digital test codes include built-in fixed and pseudo-random codes, as well as user-defined test codes entered via serial port (SPI).