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Transistor Coupled Logic

IP.com Disclosure Number: IPCOM000097406D
Original Publication Date: 1962-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Atwood, LW: AUTHOR

Abstract

This circuit provides an A-I logic function and is suitable for microelectronic packaging. The circuit operates from a single power supply, is insensitive of operating points with variations in transistor B and has very low power dissipation.

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Transistor Coupled Logic

This circuit provides an A-I logic function and is suitable for microelectronic packaging. The circuit operates from a single power supply, is insensitive of operating points with variations in transistor B and has very low power dissipation.

The circuit includes a triple-emitter transistor T1 and an inverting transistor T2. Transistor T1 includes emitters A, B and C, base electrode 20 and collector electrode 30. Transistor T2 includes base 40, collector 50 and emitter 60. The input to emitters A, B and C is supplied from collectors 50 of previous stages. Base 20 is connected through tunnel diode 70 and resistor 72 to voltage supply
74. Collector 30 and base 40 are directly connected together. Emitter 60 is grounded.

The operating characteristic of the circuit is shown in the right hand drawing and is taken at the base of T1. Curves 80 and 80' represent the operating characteristic of diode 70 for different diode characteristics. Curves 82 and 82' represent the composite characteristic for the series connection of the collector- emitter and emitter-base of T2 and T1, respectively. Curve 82 is for transistors having high beta characteristic. Curve 82' is for transistors having a low beta characteristic. Curves 84 and 84' are the composite characteristic for the series connection of the base-collector and base-emitter characteristics of T1 and T2. Curve 84 is for transistors having a low base-emitter voltage. Curve 84' is for transistors having a high base-emitter voltage.

Curves 82 and 82' intersect the curves 80 and 80' to establish a first operating region. Similarly, curves 84 and 84' intersect curves 80 and 80' to establish a second...