A new transresistance-mode instrumentation amplifier with low number of MOS transistors and electronic tuning opportunity

Abstract

In this paper, the simplest possible electronically adjustable transresistance-mode (TRM) instrumentation amplifier (IA) using only eight MOS transistors is presented. Extremely simple structure of the proposed IA leads to a wide bandwidth and robust performance against mismatches and parasitic capacitances. Of more interest is that the differential-mode gain of the proposed IA can be electronically varied by control voltages. Post-layout and pre-layout simulation results based on 0.18µm TSMC CMOS parameters are included to confirm the validity of the theoretical analysis. Despite extremely simple structure, its input and output impedances are 1.93 and 1.68k, respectively. Time domain analysis shows that for an input signal of 20µA peak to peak, maximum value of THD is 4.5% for different frequencies. Monte Carlo simulation is also carried out, which proves robust performance of the proposed IA against mismatches. The required chip area is only 17.1×36.9µm2. © 2016 World Scientific Publishing Company.