10 - Practical considerations

Abstract

This chapter discusses the important practical points to be considered when designing and using the op-amp circuits. The performance of general-purpose op-amps is normally adequate for the majority of circuits. The choice of the op-amp type and other design decisions are made easier by a systematic design approach. To choose an op-amp for a given circuit, the designer must consider the function that it is required to perform. It is important to consider all the op-amp parameters that may influence the performance. In this regard, the op-amp performance parameters influence its behaviour in a specific application. Performance errors determine the ability of a particular op-amp to meet its desired accuracy requirement. In most applications, not all op-amp parameters have equal importance. The ability to recognize the important performance-limiting specifications simplifies th eprocess of op-amp selection. Some op-amps have a common mode range that extends down to the negative supply rail. These op-amps are specifically designed for single power supply operation. This circuit cannot be implemented directly with general-purpose op-amps, although the circuit does not work very well when the output potential is the near earth. The op-amps designed specifically for single supply operation can also be used with dual or referenced supplies, but they do not normally perform as good as the most general-purpose types.