The sonic window: second generation prototype of low-cost, fully-integrated, pocket-sized medical ultrasound device

This paper will focus on the development of the second generation Sonic Window prototype, which will occupy a package the size of a deck of cards and be capable of forming C-mode ultrasound images in real-time. An array of 3,600 full receive channels—consisting of protection circuitry, a preamplifier, tuneable bandpass filter, sampler bank, and 8-bit ADC—is formed by flip-chip attaching twelve identical 300-channel custom ICs onto a double-layer flex circuit substrate. The receive channel pitch is 200 µm x 275 µm and the entire receive circuitry array has a form factor of only 1.9 cm x 1.8 cm. The flex circuit provides I/O fanout to a beamforming PCB containing bias circuitry, programmable logic, a DSP, and LCD for image display. The receive circuitry array connects through a z-axis electrically conducting interface to a 60x60 element, 300-micron- pitch, fully-sampled transducer array inexpensively fabricated on a double-layer PCB substrate. Experimental test results from a test chip containing receive circuitry components are presented, along with a description of the 3,600-channel receive circuitry array development.