Browse Prior Art Database

Integrated Circuit Using Resistor Books

IP.com Disclosure Number: IPCOM000046063D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Pollmann, K: AUTHOR [+4]

Abstract

The standard transistor-transistor logic (TTL) circuit comprises a multi-emitter input transistor Tl controlling an output transistor T2. Resistor Rl supplies the base current for T1. Resistor R2 mainly determines the performance of the unloaded circuit, and resistor R3 mainly influences the delay adder for wiring capacitances.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 68% of the total text.

Page 1 of 2

Integrated Circuit Using Resistor Books

The standard transistor-transistor logic (TTL) circuit comprises a multi- emitter input transistor Tl controlling an output transistor T2. Resistor Rl supplies the base current for T1. Resistor R2 mainly determines the performance of the unloaded circuit, and resistor R3 mainly influences the delay adder for wiring capacitances.

As the integration density increases, the circuits become smaller and the chips larger. This widens the range of the capacitances of the networks. Generally, 50 percent of the networks are below 0.4 pF (the average being 0.8 pF), and several networks are above 10 pF. The value of resistor R3 is chosen in such a manner that at high capacitances the delay adders are not too high. Normal transistor ratios are Rl:R2:R3 = 3:2:1. With the great number of circuits having low wiring capacitances, such a low value of R3 leads to power being unnecessarily wasted. To afford a higher degree of freedom when placing the circuits, it is necessary for the masterslices to have more circuits than can be wired in the silicon. For this purpose, all 3 resistors of a cell can be used in parallel and be provided as a resistor book. In such a case, a high value can be used for R3, for example, R1:R2:R3 = 1:1:1, so that the resistor book value is a third of the value of R3.

Such a book is used only for highly capacitive networks, and it is only in those that power is consumed. Multiple application of the book is possible, f...