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Complementary Bipolar Switch Using Symmetrical Transistors

IP.com Disclosure Number: IPCOM000049678D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Cottrell, PE: AUTHOR [+3]

Abstract

This circuit provides a low impedance, high performance integrated circuit switch by interconnecting a symmetrical PNP transistor and a symmetrical NPN transistor in the form of a bridge circuit.

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Complementary Bipolar Switch Using Symmetrical Transistors

This circuit provides a low impedance, high performance integrated circuit switch by interconnecting a symmetrical PNP transistor and a symmetrical NPN transistor in the form of a bridge circuit.

As indicated in the figure, a symmetrical NPN transistor 10 has its base B1 connected to a switchable current source 12 and a PNP transistor 14 has its base B2 connected to a switchable current sink 16. The emitter/collector E1/C1 of the NPN transistor 10 and the emitter/collector E3/C3 of the PNP transistor 14 are connected to an input terminal 18, with the emitter/collector E2/C2 of the NPN transistor 10 and the emitter/collector E4/C4 of the PNP transistor 14 being connected to an output terminal 20. As is known, the emitters/collectors E1/C1, E2/C2, E3/C3 and E4/C4 will act either as emitters or collectors depending upon the polarity of the voltages applied thereto.

The switchable current source 12 and the switchable current sink 16 may be provided by any conventional circuit, e.g., by the use of a current mirror circuit, and the symmetrical transistors 10 and 14 may be made as described in the IBM Technical Disclosure Bulletin 17, 2574 (February 1975) or as described in the preceding article.

This analog switch is particularly useful in sample and hold, multiplexing or other such applications.

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