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I(CEX) Test Circuit for Discrete Transistors

IP.com Disclosure Number: IPCOM000056420D
Original Publication Date: 1980-Dec-01
Included in the Prior Art Database: 2005-Feb-14

Publishing Venue

IBM

Related People

Authors:
Radcliffe, WE [+details]

Abstract

The transistor parameter I(CEX) is difficult to measure on commercial test systems without the use of a floating battery. I(CEX) is defined as the collector leakage current with the base-to-collector junction reverse biased and with the base-to-emitter junction reverse biased or slightly forward biased. Most commercial test systems measure the I(CEX) parameter using a circuit such as the one shown in Fig. 1. In this circuit, only a completely isolated power supply (battery) can be used. A conventional power supply has a large capacitor (C(1)) between the output and ground plus common mode noise. This noise causes a problem when the I being measured is in the 10-1000 nA range.