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).

Bipolar integrated circuits in SiC for extreme environment operation

“…Analog circuits have only been tested up to 500 °C, but work as expected from modeling. This includes operational amplifiers [49,50,55], differential amplifiers [39], latched comparators [52], Schmitt triggers [51], voltage regulators [56], drivers [57], BGVRs [42], DACs [54], and even a Sigma-Delta modulator [53]. The main characteristics are listed in table 2.…”

“…Some basic analog designs were also tested, such as Darlington pairs [38] and Schmitt triggers [51]. A latched comparator [52] and fully differential amplifier [39] were made separately as building blocks for a Sigma-Delta modulator [53]. An integrated digital-to-analog con-verter(DAC) has also been made [54].…”