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Minimally Isolated Current Switch Emitter Follower Circuits

IP.com Disclosure Number: IPCOM000076663D
Original Publication Date: 1972-Apr-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Cass, EE: AUTHOR

Abstract

This monolithic integrated circuit arrangement minimizes the silicon area required for the components of current-switch emitter-follower circuits, so that the actual size of the circuit cell is determined by wiring channels and interconnection technology. This minimizes the manufacturing cost. The layout is unique in that it locates in the same isolation region, several active devices which conventionally are isolated from each other.

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Minimally Isolated Current Switch Emitter Follower Circuits

This monolithic integrated circuit arrangement minimizes the silicon area required for the components of current-switch emitter-follower circuits, so that the actual size of the circuit cell is determined by wiring channels and interconnection technology. This minimizes the manufacturing cost. The layout is unique in that it locates in the same isolation region, several active devices which conventionally are isolated from each other.

The schematic circuit diagram is shown in Fig. 1. It is obvious that the current-switch transistors T3 to T6, inclusive, can be put in the same isolation region. Furthermore, all active devices and collector resistors can be put in the same isolation region. In the case of the present circuit, two isolation regions are required because of the interconnection arrangement.

Fig. 2 shows the layout of the diffusion regions and contact holes for the circuit shown schematically in Fig. 1. The letter "E" designates the emitters; the letter "B" designates the bases; the letter "C" designates the collectors; the letter "T" designates the transistors; the letters "BCH" designate the base contact holes; the letters "CCH" designate the collector contact holes; and the suffix numerals distinguish the several transistors. The two isolation regions are designated by the Roman numerals 1 and 11, respectively.

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