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Method of Improving Match on Integrated Resistors

IP.com Disclosure Number: IPCOM000088898D
Original Publication Date: 1977-Aug-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bergeron, DL: AUTHOR [+2]

Abstract

This technique makes use of the voltage coefficient of resistance (VCR) to improve the match of two resistors in an epitaxial (epi) bed in integrated circuits.

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Method of Improving Match on Integrated Resistors

This technique makes use of the voltage coefficient of resistance (VCR) to improve the match of two resistors in an epitaxial (epi) bed in integrated circuits.

It is known that the resistance of an integrated resistor changes with voltage and that the rate of change decreases with voltage.

It has been found that the voltage coefficient of resistance is given by: VCR = (R(V)(1) - R(V)(0))/Delta V(eff') where Delta V(eff) = V(1)-V(0) where V(eff) is a function of the drop across the resistor and the epi bias given by V(eff) = .5V(R) + (V(epi) - V(RP)) where V(R) = voltage drop across the resistor V(epi) = epi bias V(RP) = voltage on positive end of resistor.

By biasing the epi such that V(epi) >> VR, the change in resistance due to the change in V(R) becomes negligible and two resistors operating at different VRs will each approach a constant value.

Hence by biasing the epi at a high voltage, the effects of an external circuit operating on the matched resistors can be diminished.

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