Choosing a low-noise amplifier

摘要

A discussion of low-noise amplifiers usual-ly brings to mind RF/wireless applications. However, noise is also a critical consideration for lower-frequency analog applications such as buffering data converters, amplifying strain-gauge signals, and preamplifying microphone outputs. Before selecting an appropriate amplifier, an engineer must first understand the noise parameters that determine whether an amplifier is low noise. Additionally, it's imperative to understand that the type of IC—bipolar, 'JFET-input, or CMOS-input—determines these parameters.