特种传声器管可靠性分析

Analysis on Reliability of the Special Device

驻极体电容传声器(简称话筒)其专用结型场效应(JFET)与正向箝位二极管D1组成简单组合器件,称之为传声器管。该产品由P+N结栅控制沟道电流,不同于MOST的绝缘栅结构。因此在设计中并没有静电放电(ESD)防护装置。并且执行的标准截然不同,随着传声器管的应用逐渐扩大,要求提高电性能;为了抗射频(RF)噪声干扰在传声器管芯片中,集成一个10～30 pF,PN结电容器。同时又能对原有的P+N结起到保护,提高了静电击穿的效果,因而,扩展了传声器管的应用领域。

The junction type field effect transistor（JFET）is specially used in electret conderser microphone.The JFET and the forward champing diode D1 are combined into the simple combined device.It is different from the insulation gate structure of MOST,its channel current is controled by P＋N junction gate.So,it has no electro-static discharge（ESD）protection equipment in its design.And its executive standard is different.with the enlargement of JFET＇S application,its eletricity performance should be improved.In order to resist the interference of RF noise,and protect the former P＋N junction,in JFET＇S die,integrate a 10~30pF＇S PN junction condenser to improve the effect of electro static breakdown,thus expend the application of JFET.