A Ping-Pong Auto-Zero Instrumentation Amplifier Design

Abstract

A ping-pong auto-zero instrumentation amplifier is presented in this paper. Ping-pong structure is utilized for fast calibration speed. Folded-cascode with class AB output structure are utilized as main amplifier. Folded-cascode with gain boosting structure are utilized as auxiliary amplifier. Both amplifier has a pair of additional input terminals for offset calibration. Simulation results show that the offset voltage is 0.7μV, DC gain is 150dB, unity gain bandwidth of main amplifier is 1.9MHz, common-mode rejection ratio is 130dB, and power consumption is 1.4mW. The design of this amplifier is based on 0.5μm CMOS process with a single supply voltage of 5V.