Highly linear differential CMOS transconductance amplifiers

Two novel input stages for CMOS operational transconductance amplifiers (OTAs) with wide linear input ranges are proposed. The first is simpler and performs well only with full differential input signals, and the second performs well with both full differential and common mode input signals. Nonlinear errors less than 1% at DC and a THD less than -40 dB at 1 MHz with ±9-V input signals were observed when simulating OTAs using these differential input stages fed with ±10 V DC