A 500 °C Monolithic SiC BJT Latched Comparator

Abstract

This paper presents a monolithic 4H-SiC BJT latched emitter-coupled logic (ECL) comparator for high temperature analog-to-digital conversion. The comparator consists of a low-gain pre-amplifier, a track and latch stage and an output buffer. For low-speed input signals, the comparator input offset voltage is 3.9 mV at 27 °C and monotonically increases up to 9.1 mV at 500 °C. The single-ended output swing is 5.5 V at 27 °C and 3.9 V at 500 °C. The minimum comparison time is around 1μs from 27 °C to 500 °C. The whole comparator dissipates 464 mW in average over the considered temperature range with a 15 V power supply. It consumes 2.25 × 0.84 mm2 chip area (with the bond pads included).