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REVERSE STRESS PROTECTION FOR THE EMITTER-BASE JUNCTON OF ECL GATES

IP.com Disclosure Number: IPCOM000005706D
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2001-Oct-29
Document File: 1 page(s) / 39K

Publishing Venue

Motorola

Related People

Bor Yuan Hwang: AUTHOR

Abstract

Diodes 1 and/or 2 are provided in the ECL gates of figures 1 and 2 for reducing the reverse voltage across the base-emitter junction of transistor 1 when the input is open.

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MOTOROLA Technical Developments Volume 8 October 1988

REVERSE STRESS PROTECTION FOR THE EMITTER-BASE JUNCTON OF ECL GATES

by Bor Yuan Hwang

Diodes 1 and/or 2 are provided in the ECL gates of figures 1 and 2 for reducing the reverse voltage across the base-emitter junction of transistor 1 when the input is open.

   With diodes 1 and 2 missing from the circuits and the input being open, transistor 1 has a -3.2 volt and -2.4 volt reverse bias across the emitter-base junctions for figures 1 and 2, respectively. This reverse bias may cause long term reliability problems since emitter-base junctions generally have very low breakdown voltages.

   Leakage current from the reverse biased emitter-base junction biases diodes 1 and 2 to approximately 1.0 to 1.5 volts, thereby reducing the reverse voltage across the emitter-base junction by approximately 1.0 to 1.5 volts. Polysilicon diodes are recommended to reduce parasitics associated with diodes 1 and 2 and improve performance.

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0 Motorola, Inc. 1988 21

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