同樣都是過壓防浪涌保護，為什么人家的電路保護方案就是比你的優秀呢？工欲善其事，必先利其器，要想運用好TVS管，就必須熟練掌握TVS管(guan)的關鍵參數。接下來，專業高品質電路保護器件廠家——東沃電子，傾心為您科普有關TVS管參數的知識。

1）Vrwm截止電壓
TVS管(guan)的最高(gao)(gao)工(gong)作(zuo)電(dian)(dian)壓，可連續施加而不引起(qi)TVS管(guan)劣化(hua)或損(sun)壞的最高(gao)(gao)工(gong)作(zuo)峰(feng)值(zhi)電(dian)(dian)壓或直(zhi)流峰(feng)值(zhi)電(dian)(dian)壓。在Vrwm下，TVS管(guan)是不工(gong)作(zuo)的，即不導通的。也就是說，電(dian)(dian)路(lu)的最高(gao)(gao)工(gong)作(zuo)電(dian)(dian)壓必須小于Vrwm，否則會引起(qi)TVS管(guan)動作(zuo)導致(zhi)電(dian)(dian)路(lu)異常。

2） I R 漏電流
漏(lou)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)，也稱待(dai)機電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)。在規定(ding)溫度和(he)最(zui)高(gao)工作(zuo)電(dian)(dian)(dian)壓(ya)(ya)條(tiao)件下，流(liu)(liu)(liu)(liu)(liu)過TVS管的最(zui)大(da)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)。TVS管的漏(lou)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)一般是在截止電(dian)(dian)(dian)壓(ya)(ya)下測量，對(dui)于某一型號TVS管, I R 應在規定(ding)值(zhi)(zhi)范圍內。對(dui) TVS 兩端施加電(dian)(dian)(dian)壓(ya)(ya)值(zhi)(zhi)為Vrwm ，從電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)表(biao)中讀(du)出的電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)值(zhi)(zhi)即為TVS的漏(lou)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu) I R 。對(dui)于同功率和(he)同電(dian)(dian)(dian)壓(ya)(ya)的TVS，在Vrwm≤10V 時(shi)，雙(shuang)向(xiang) TVS 漏(lou)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)是單向(xiang) TVS 漏(lou)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)的2倍(bei)。對(dui)于一些(xie)模擬(ni)端口，漏(lou)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)會影響AD的采樣值(zhi)(zhi)，所以(yi)TVS的漏(lou)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)越小(xiao)越好。

3）VBR 擊穿電壓
擊穿電壓，指在 V-I 特性曲線上，在規定的脈沖直流電流I T或接近發生雪崩的電流條件下測得TVS管兩端的電壓。測試的電流I T一般選取10mA左右，施加的電流的時間不應超過400ms，以免損壞器件，VBRmin和 VBRmax是TVS管擊穿電壓的一個偏差，一般 TVS 管為±5%的偏差。測量時，V BR 落在 V BRmin和 V BRmax 之間視為合格品。

4）I PP 峰值脈沖電流和V C 鉗位電壓
峰值(zhi)脈沖(chong)(chong)(chong)電(dian)(dian)(dian)(dian)流(liu)(liu)，給定(ding)(ding)脈沖(chong)(chong)(chong)電(dian)(dian)(dian)(dian)流(liu)(liu)波(bo)(bo)形的(de)峰值(zhi)。TVS二(er)極(ji)(ji)管(guan)(guan)一般(ban)選用 10/1000μs 電(dian)(dian)(dian)(dian)流(liu)(liu)波(bo)(bo)形。鉗位電(dian)(dian)(dian)(dian)壓，施加規定(ding)(ding)波(bo)(bo)形的(de)峰值(zhi)脈沖(chong)(chong)(chong)電(dian)(dian)(dian)(dian)流(liu)(liu) I PP 時(shi)，TVS二(er)極(ji)(ji)管(guan)(guan)兩端(duan)測(ce)得的(de)峰值(zhi)電(dian)(dian)(dian)(dian)壓。I PP 及(ji) V C 是衡量TVS二(er)極(ji)(ji)管(guan)(guan)在(zai)電(dian)(dian)(dian)(dian)路(lu)保(bao)護中抵抗浪涌脈沖(chong)(chong)(chong)電(dian)(dian)(dian)(dian)流(liu)(liu)及(ji)限制(zhi)電(dian)(dian)(dian)(dian)壓能(neng)力的(de)參(can)數(shu)，這兩個參(can)數(shu)是相互聯系的(de)。對(dui)于(yu)TVS二(er)極(ji)(ji)管(guan)(guan)在(zai)防雷(lei)保(bao)護電(dian)(dian)(dian)(dian)路(lu)中的(de)鉗位特性(xing)，可(ke)以參(can)考V C這個參(can)數(shu)。對(dui)于(yu)相同型號TVS二(er)極(ji)(ji)管(guan)(guan)，在(zai)相同I PP下的(de)V C越(yue)(yue)小，說明(ming)TVS二(er)極(ji)(ji)管(guan)(guan)的(de)鉗位特性(xing)越(yue)(yue)好。TVS二(er)極(ji)(ji)管(guan)(guan)的(de)耐脈沖(chong)(chong)(chong)電(dian)(dian)(dian)(dian)流(liu)(liu)沖(chong)(chong)(chong)擊能(neng)力可(ke)以參(can)考 I PP ，同型號的(de)TVS二(er)極(ji)(ji)管(guan)(guan)，I PP 越(yue)(yue)大，耐脈沖(chong)(chong)(chong)電(dian)(dian)(dian)(dian)流(liu)(liu)沖(chong)(chong)(chong)擊能(neng)力越(yue)(yue)強。

5）結電容C
結電容是TVS二極管中(zhong)的寄生電容，在高速IO端口(kou)保護需要重點關注(zhu)，過大(da)的結電容可能(neng)會影響信號的質(zhi)量。

了解熟悉TVS二極管的基本參數之后，正式進入到重要的環節：TVS二極(ji)管選型。