Tutorial on Resistor Trimming

Abstract

It is expensive if not impossible to fabricate embedded resistors to the correct resistance value. Therefore, embedded resistor is often fabricated with a typical value and then use a post-fabrication trimming process to trim it to the desired value. This tutorial discusses how to set up the resistor network appropriately to achieve the desired resistance through trimming. The trimming strategy is studied analytically, with a number of variations in the trimming topologies. A voltage reference circuit is applied as the underneath application in this tutorial such as to provide more concrete discussions on the physical meaning of trimming accuracy.