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Monolithic Diode Transistor Logic Circuitry

IP.com Disclosure Number: IPCOM000087556D
Original Publication Date: 1977-Feb-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 98K

Publishing Venue

IBM

Related People

Eichelberger, EB: AUTHOR [+2]

Abstract

Referring to Figs. 1A and 1B, a diode-transistor logic circuit is depicted employing a single collector diffusion with multiple Schottky diode outputs Y1, Y2 and Y3. Logic may be performed by connecting two or more circuit outputs (Yi) of different logic circuits together to provide a "dot AND" function. The output of the "dot AND" is connected to the input (X) of a further logic circuit. For proper operation, the forward voltage drop of the Schottky diodes d1 must be less than Vbe + Vce (saturation) of the transistor T1. Also, voltage +V must be greater in magnitude than Vbe. The collector resistor R2 and a high forward voltage drop Schottky diode d2 may be employed to improve the performance of the logic circuit [*].

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Monolithic Diode Transistor Logic Circuitry

Referring to Figs. 1A and 1B, a diode-transistor logic circuit is depicted employing a single collector diffusion with multiple Schottky diode outputs Y1, Y2 and Y3. Logic may be performed by connecting two or more circuit outputs (Yi) of different logic circuits together to provide a "dot AND" function. The output of the "dot AND" is connected to the input (X) of a further logic circuit. For proper operation, the forward voltage drop of the Schottky diodes d1 must be less than Vbe + Vce (saturation) of the transistor T1. Also, voltage +V must be greater in magnitude than Vbe. The collector resistor R2 and a high forward voltage drop Schottky diode d2 may be employed to improve the performance of the logic circuit [*].

As depicted in Figs. 2A and 2B, the collectors of two or more circuits may be "dotted" together to form an additional level of logic having a single circuit delay. Thus, as shown in Fig. 2B two (or more) levels of logic may be accomplished employing a single collector diffusion.

A Weinberger (U. S. Patent 3,475,621) arrangement of diode-transistor logic circuits is depicted in Fig. 3. This arrangement requires only a single level of metal for interconnection. This arrangement has utility as a logic masterslice with one level of metal, or to fabricate complex macro-functions without blocking second level wiring. [*] C. L. Schuenemann and S. K. Wiedmann, "Schottky- Diistor Logic," IBM Technical Disclosure B...