Patent ID: 7667156

Claim:
A method for trimming a parameter of a resistor made from a thermally mutable material, the method comprising: (a) in a first step, subjecting said resistor to a high first temperature by applying at least one heat pulse, to trim said parameter of said material in a first direction away from an original value; (b) in a second step, subjecting said resistor to a second temperature lower than said high first temperature by applying at least one heat pulse, so as to trim said parameter of said material in an opposite direction back towards said original value with a rate of change in said parameter that is initially rapid and gradually decreasing to a first level; and (c) in a third step, subjecting said resistor to a third temperature lower than said second temperature by applying at least one heat pulse, so as to trim said parameter in said opposite direction with said rate of change in said parameter that is greater than said first level.