`Class A` refers to configuring an amplifier so that its output devices remain turned on all the time. This reduces thermal variation and eliminates crossover distortion, which makes the chip perform better. To bias an op-amp into class A, you simply put a current source from the op-amp`s output to one of the power rails. Everything else is details. This article is about those details.
An ideal current source is any device that will pass a constant amount of current no matter what the voltage drop across it is. Naturally, there is no such thing as an ideal current source, so this article will describe several alternatives of increasing