A High CMRR, High Slew Rate, Low Total Harmonic Distortion CMOS OTA for HF Applications

A balanced OTA which is the simplest configuration of an operational transconductance amplifier is chosen as a basic building block for the present work and the performance is verified in terms of CMRR, slew rate and total harmonic distortion (THD). A design procedure has been adopted to improve the circuit behaviour. The resulting OTA has improvement as compared to the basic balanced OTA in terms of better CMRR, slew rate and lower THD. Further, the improved circuit of balanced OTA is used to implement tunable OTA. The tunable OTA designed in the present work has CMRR of 56 dB, slew rate of 1.6 V/ns and total harmonic distortion of 0.6%. The circuits are implemented in 130 nm using TSMC MOSIS Level-49 model in HSPICE simulator and the physical implementation (layouts) has been done in Tanner EDA L-Edit.