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Grounded Base Transistor Gated AND Circuit

IP.com Disclosure Number: IPCOM000092637D
Original Publication Date: 1966-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Day, RC: AUTHOR

Abstract

Substituting individual transistors for the input diodes utilized in diode-coupled transistor logic circuitry minimizes the up-level signal degradation previously exhibited by such circuitry. Monolithic circuit fabrication techniques enable this modification to be accomplished readily.

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Grounded Base Transistor Gated AND Circuit

Substituting individual transistors for the input diodes utilized in diode- coupled transistor logic circuitry minimizes the up-level signal degradation previously exhibited by such circuitry. Monolithic circuit fabrication techniques enable this modification to be accomplished readily.

Transistors 10 and 12 with their associated resistors 14, 16, and 18 comprise an And. Inputs are applied at terminals 20, 22, and 24. An output signal is available at terminal 26. Disposed between terminal 22 and signal source 28 is transistor 30 and associated resistor 32. Similar circuits 34 and 36 disposed between terminals 20 and 24 and signal sources 38 and 40 are shown in phantom.

In fabricating monolithic diodes, a transistor structure is formed initially. The base and collector regions are then shorted together. Since a transistor structure is available initially, it now becomes possible to utilize that transistor, with its attendant advantages, as a substitute for the previously employed diodes. A fabrication step is thus eliminated as well.

The underlying principle of substituting individual transistors for individual diodes in diode-coupled transistor logic can be extended to other logic circuits, such as Or and latch circuits.

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