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Low Input Bias Current Amplifier

IP.com Disclosure Number: IPCOM000054165D
Original Publication Date: 1980-Jan-01
Included in the Prior Art Database: 2005-Feb-13

Publishing Venue

IBM

Related People

Authors:
Buhler, OR Marino, PT [+details]

Abstract

In integrated circuits operating with low power supply voltage, requirements arise in bipolar integrated circuits for a low input bias current requirement. A good choice is the so-called Darlington emitter follower for reducing input bias current. In low voltage applications, the extra base to emitter drop of the additional transistor may be unacceptable as being excessive. Sometimes a PNP and NPN can be paired together for accommodating the excessive base to emitter drop; however, the h(fe) of the PNP device often is not as high as the h(fe) of the equivalent NPN device and does not give as low an input current as a Darlington pair.