ABSTRACT
This chapter concentrates on opamps. It focuses on achieving the best possible performance rather than cutting the last penny off the costing sheet. The 5532 is a low-noise, low-distortion bipolar dual opamp with internal compensation for unity-gain stability. The 5532 and 5534 type opamps require adequate supply decoupling if they are to remain stable; otherwise they appear to be subject to some sort of internal instability that seriously degrades linearity without being visible as oscillation on a normal oscilloscope. Audio power amplifiers have discrete input stages which are very simple compared with those of most opamps and draw relatively large input currents. For a unity-gain shunt-feedback stage the opamp noise gain is 2 times. The LM4562 is a relatively new opamp which first become freely available at the beginning of 2007. It is a National Semiconductor product. The LME49990 from National Semiconductor is a single opamp available only as an 8-lead narrow body SOIC surface-mount package.
