Analog Circuit Design Volume 2

Chapter 19

Unique IC buffer enhances op amp designs, tames fast amplifiers

Robert J. Widlar

Acknowledgement

Thanks are due to Felisa Velasco for special engineering assembly which was key to product development and to Guy Hoover for doing most of the experimental work presented here.

Abstract

A unity gain IC power buffer that uses NPN output transistors while avoiding the usual problems of quasi-complementary designs is described. Free of parasitic oscillations and stable with large capacitive loads, the buffer has a 20MHz bandwidth, a 100V/μs slew and can drive ±10V into a 75Ω load. Standby current is 5mA. A number of applications using the buffer are detailed, and it is shown that a buffer has many uses beyond driving a heavy load.

Introduction ...