Op Amps for Everyone, 5th Edition

Chapter 7

Development of the Nonideal Op Amp Equations

Abstract

Applying feedback theory and Bode analysis to real-world op amp circuits reveals that real-world gain circuits behave differently than circuits constructed with ideal op amp models. In particular, the limitation on open-loop gain affects and reduces the gain of common op amp circuits. The open-loop response of an op amp forms an unbreachable limit to where an op amp can operate.

Keywords

Closed-loop gain; Closed-loop response; Open-loop gain; Open-loop response

7.1. Introduction

There are two types of error sources in op amps, and they fall under the general classification of DC and AC errors. Examples of DC errors are input offset voltage and input bias current. The DC errors stay constant ...