ST TS472非常低噪音麦克风前置放大方案

ST 公司的TS472是非常低噪音麦克风前置放大器,全差分输入/输出, F = 1 kHz时输入等效噪音为10 nV/√Hz,单电源2.2V-5.5V工作,典型失真为0.1%,主要用在视频照相机声音输入,声音采集和语音识别,视频会议系统,笔记本电脑和PDA.本文介绍TS472主要特性,典型应用电路,单端输入应用电路和演示板STEVAL-CCA023V1主要特性与电路图.

Very low noise microphone preamplifier with 2.0 V bias output and active low standby mode The TS472 is a differential-input microphone preamplifier optimized for high-performance PDA and notebook audio systems.

This device features an adjustable gain from 0 to 40 dB with excellent power-supply and commonmode rejection ratios. In addition, the TS472 has a very low noise microphone bias generator of 2 V.

It also includes a complete shutdown function, with active low standby mode.

TS472主要特性:

■ Low noise: 10 nV/√Hz typ. equivalent input noise at F = 1 kHz

■ Fully-differential input/output

■ 2.2 to 5.5 V single supply operation

■ Low power consumption at 20 dB: 1.8 mA

■ Fast start up time at 0 dB: 5 ms typ.

■ Low distortion: 0.1% typ.

■ 40 kHz bandwidth regardless of the gain

■ Active low standby mode function (1 uA max)

■ Low noise 2.0 V microphone bias output
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