一种基于互补双极工艺的大动态范围对数放大器

A Wide Dynamic Range Logarithmic Amplifier With Complementary Bipolar Process

基于自主互补双极工艺,设计了一种单片大动态范围对数放大器,介绍了对数放大器总体架构以及工作原理。电路内部包含限幅放大器、整流器、偏置电路、输出级、失调补偿结构等单元,对对数放大器结构特点和实现原理进行了分析。芯片流片测试结果表明,该对数放大器在5 V工作电压条件下,工作频率DC-500 MHz;对数斜率23~27 mV/dB;对数截距-87~-77 dBm;输入失调电压≤500μV;电源电流≤14 mA;在对数精度±1 dB要求下,动态范围可达到80 dB以上;在对数精度±3 dB要求下,动态范围可达到88 dB以上;响应时间≤600 ns。

Based on low-voltage complementary bipolar process,a wide dynamic range logarithmic amplifier was presented.The overall structure and working mechanism of logarithmic amplifier circuit were introduced.The circuit is consisted of limiting amplifiers,amplitude detectors,a biasing circuit,an output stage and offset nulling structure.This article analyzed the feature of structure and the realizing principle.Test results indicate that,under 5 V power supply conditions,the device has working frequency of DC-500 MHz,logarithmic slope 23~27 mV/dB,logarithmic intercept-87~-77 dBm,input offset voltage≤500μV,power supply current≤14 mA.The±1dB dynamic range≥80 dB,the±3 dB dynamic range≥88 dB.The response time≤600 ns.