A High-Speed and High-Linearity BiCMOS Optically Coupled Isolation Amplifier

Abstract

To improve the current non-linear optically coupled isolation amplifier and high power consumption, we designed a low-power, high-speed and high-linearity BiCMOS optically isolation amplifier. There are only two push-pull output stages configuration bipolar transistor (BJT) in the design process, the rest of the circuit is the CMOS device. To improve amplifier gain linearity and stability, we introduce the complementary symmetrical photodiode, in the optically coupled part and every amplifier, negative feedback is introduced. Experimental results indicate that the design of optically isolation amplifier ± 3 dB bandwidth increases 40 kHz than optically isolation amplifier ISO100 bipolar, When the power supply voltage is 4.8 V, the delay - power product of DP is lower than ISO100 37.3 pJ, gain linearity is up to 5.5 × 10-5, which is suitable for high-speed control system.