Analog Circuit Design

12

Performance verification of low noise, low dropout regulatorsSilence of the amps

Jim Williams and Todd Owen

Introduction

In an increasing trend, telecommunications, networking, audio and instrumentation require low noise power supplies. In particular, there is interest in low noise, low dropout linear regulators (LDOs). These components power noise-sensitive circuitry, circuitry that contains noise-sensitive elements or both. Additionally, to conserve power, particularly in battery driven apparatus such as cellular telephones, the regulators must operate with low input-to-output voltages.¹ Devices presently becoming available meet these requirements (see separate section, “A family of 20μV_RMS noise, low dropout regulators”).

Noise and noise testing ...