A mixed-signal BiCMOS front-end signal processor for high-temperature applications

A mixed-signal ASIC that implements an ultrasound front-end receiver in a 0.6 /spl mu/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 clock frequency and 200/spl deg/C, the power consumption is 85 mW from a single 5 V supply. The die area of the chip is 5.52 mm/sup 2/.