Operational Amplifiers
Introduction 2.7 effec of Finite Open-Loop
2.1 The Op-Amp Terminals and Bandwidth on Circuit
2.2 The ideal Op Amp performance
2.3 Anlysis ofcircuits Cotaining 2.8 Large-Signal Operation of
Ideal Op amp-The inverting Op amps
Configuration 2.9 DC lmperfections
2.4 Other Applications Of the Summary
Inverting Configuration Bibilograaphy
2.5 The noninverting Configuration Problems
2.6 Examples of op-amp Circuits
Introduclon
Having lerned basic amplifier concepts and terminology, We are now ready to undertake study of a circuit building block of universal importance: the operational amplifier (opamp). Although op amps have been in use for a long time, their applications wave initially in the areas of analog computation and instrumentation. Early op amps were constructed from discrete components (vacuum tubes and then transistors, and resistors), and their cost was prohibitively high (tens of dollars). In the mid -1960s the first integrated-circuit (IC) op amp was produced. This unit (the uA 709) was made up of a relatively large number of transistors and resistors all on the same silicon chip. Although its characteristics were poor(by today”s standards) and its price was still quite high, its appearance signaled a new ear in electronic circuit design Electronits engineers started using op amps in large quantities, which caused their price to drop dramatically. They also demanded better-quality op amps. Semiconductor manufacturers responded quickly; and within the span of a few years, high-quality op amps became available at extremely low prices (tans of cents) from a large number of suppliers.
One of the reasons for the popularity of the op amp is its versatility. As we will shortly
See, one can do almost antthing with op amps! Equally important is the fact that the IC op amp has characteristics that closely approach the assumed ideal. This implies that it is quite easy to design circuits using the IC op amp. Also, op amp circuits work as levels that are quite close to their predicted theoretical performance. It is for this reason that we are study-ing op amps at this early stage. It is expected that by the end of this chapter the reader should be able to design nontrivial circuits successfully using op amps.
As already implied, an IC op amp is made up of a large number of transistors, resistors, and(usually) one capacitor connected in a rather complex circuit. Sing we have not yet studied transistor circuits, the circuit inside the op amp will not be discussed in this chapter Rather, we will treat the op amp as a circuit building block and study ist terminal charac- terisics and its applications. This approach is quite satisfactory in many op-amp applica-tions. Nevertheless, for the more difficult and demanding applications it is quite useful to know what is inside the op-amp package. This topic will be studied in Chapter 10. Finally, it should be mentioned that more advanced applications of op amps will appear in later chapters.
2.1 THE OP-AMP TERMINLS