4–20mA optical sensor at 300C using SiC and SOI integrated circuits

Abstract

Abstract GE is reporting test results from a hybrid circuit using high temperature capable resistors, capacitors, silicon carbide devices and silicon-on-insulator integrated circuits. The sensing circuit converts photodiode current to an industrial standard 4 to 20 mA output using a two wire configuration. Input currents at levels from 0pA to 30nA is converted to 4 to 20 mA using a gain compression technique and tested from room temperature to 300°C. Further, we show the circuit operating at 300°C for more than 2000 hours without failure.