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Long Narrow High Density T/2/L Receiver Circuit Layout

IP.com Disclosure Number: IPCOM000083372D
Original Publication Date: 1975-May-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Chang, C: AUTHOR [+3]

Abstract

A T/2/L circuit can be implemented with higher density if the cell is constructed with a long and narrow shape, as illustrated in Fig. 1. The cell consists of a Schottky clamped long base multiemitter input transistor, a Schottky clamped output transistor and three resistors placed at the ends of the long cell, as illustrated.

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Long Narrow High Density T/2/L Receiver Circuit Layout

A T/2/L circuit can be implemented with higher density if the cell is constructed with a long and narrow shape, as illustrated in Fig. 1. The cell consists of a Schottky clamped long base multiemitter input transistor, a Schottky clamped output transistor and three resistors placed at the ends of the long cell, as illustrated.

The long, narrow ceil provides a plurality of dynamic terminals (emitter locations for T/2/L circuit input). This means, the internal cell offers a high plurality of first-level vertical wiring channels which are free and clear across the chip. In addition, the cell also provides two (circuit output) global second-level horizontal wiring channels.

The inverse beta or the input device is a strong function of the emitter location. The inverse beta can be one order of magnitude smaller for an emitter located beyond the center of the base, as opposed to the near end off the base (at Ic >/- 0.4 ma). Fig. 3 shows the inverse beta variation vs. Ic as a function of emitter locations. The reason for small inverse beta for an emitter located at the far end, is the fact that the distributed extrinsic base-collector diodes shunts most of the base current before it reaches the emitter. This means that with restricted placement of the emitter locations beyond the base midpoint, the same T/2/L circuit can be used as a receiver circuit for an off-chip collector drive circuit, by removing the Schottky c...