Abstract
A mixed-signal ASIC that implements an ultrasound front-end receiver in a 0.6 m BiCMOS HotASIC technology that features metal/metal capacitors and poly1/poly2 resistors is described. The ASIC includes a low-noise amplifier (LNA), a programmable gain amplifier (PGA), an output differential amplifier (ODA), and a second-order sigma-delta modulator (SDM), and is the most compact system for high-temperature ultrasound applications reported in literature. The circuit has a programmable gain and is designed for measuring the signal response (200 kHz to 700 kHz) from an ultrasound transducer. At 48 MHz clockfrequency and 200 C, the power consumption is 85 mW from a single 5 V supply. The die area of the chip is 5.52 mm2.Index Terms—Array signal processing, BiCMOS integrated circuits, high-temperature electronics, mixed analog–digital integrated circuits, sigma-delta modulation, ultrasonic imaging.