Symmetric and complementary differential amplifier

摘要

A complementary differential amplifier includes two differential amplifiers. Each differential amplifier includes two input FETs (or bipolar transistors) having gate terminals coupled to the input terminals of the complementary differential amplifier. Two current load p-type field-effect transistors are each coupled in series between one voltage source and a drain terminal of a respective input FET. A current source FET is coupled in series between a common source terminal of the two input n-type field-effect transistors and a low voltage source. Only two FETs are needed to bias all of the current load and source FETs. A complementary folded cascode stage as well as an inverter stage may also be included.