High speed op amps: Performance, process and topologies

Complementary bipolar processes developed in the mid 1980's allowed the development of integrated circuit operational amplifiers with bandwidths over 50MHz [1]. In the early 1990's, complementary bipolar processes implemented on SOI extended the attainable bandwidth to 1GHz. In the new millennium, SOI processes incorporating SiGe heterojunction transistors are used to produce IC op amps with bandwidths to nearly 10GHz. Industry trends towards lower supply voltages have made low voltage design techniques increasingly important. Class A/B circuit techniques exploiting complementarity have enhanced slew and distortion performance versus supply current. The demand for low supply voltage operation and differential signal processing has driven the development of differential amplifier topologies.