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Monolithic Circuit with Pinch Resistor

IP.com Disclosure Number: IPCOM000073775D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Wiedmann, SK: AUTHOR

Abstract

A monolithic power switching flip-flop circuit is provided with a relatively high-valued collector resistor for each of two cross-coupled transistors. The resistors are shunted by conducting diodes during addressing operations. Operational stability is enhanced during addressing operations by the provision of relatively low-valued resistors in series with the shunting diodes. Such a flip-flop circuit is represented by drawing A. Cross-coupled transistors 1 and 2 are provided with relatively high-valued collector resistors RC1 and RC2 which are shunted, respectively, by diode D1 in series with resistor R11 and by diode D2 in series with resistor R12. Resistors R11 and R12 are of small value relative to resistors RC1 and RC2.

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Monolithic Circuit with Pinch Resistor

A monolithic power switching flip-flop circuit is provided with a relatively high- valued collector resistor for each of two cross-coupled transistors. The resistors are shunted by conducting diodes during addressing operations. Operational stability is enhanced during addressing operations by the provision of relatively low-valued resistors in series with the shunting diodes. Such a flip-flop circuit is represented by drawing A. Cross-coupled transistors 1 and 2 are provided with relatively high-valued collector resistors RC1 and RC2 which are shunted, respectively, by diode D1 in series with resistor R11 and by diode D2 in series with resistor R12. Resistors R11 and R12 are of small value relative to resistors RC1 and RC2.

Each relatively high-valued resistor is conveniently formed as a "pinch" resistor in the base diffusion area also shared by a respective double-emitter transistor as shown in the plan view of Drawing B. Base junction 3 is formed in collector material 4 and emitters E21 and E22 are diffused in the base area along with diffusion 5 which straddles base junction 3 to form a "pinch" resistor between ohmic contacts Q and B2. Ohmic contact C2 is formed above subcollector 6 which extends below emitter E22. Drawing C depicts the equivalent circuit for the structure shown in drawing B (a symmetrical half of the flip-flop circuit of drawing A). Diode D2 primarily is provided by the junction between the base area su...