A compound resistor is used to compensate for trimming induced shift in temperature coefficient of resistance of a trimmable resistor. The compound resistor is composed of a first and second portion, at least one of the two portions being thermally trimmable, and the parameters for the first and second portion are selected such that the trimming induced shift can be minimized on an overall resistance and temperature coefficient of resistance of the compound resistors by trimming the trimmable resistor. The invention also allows for exploring trimming range available via true thermal trimming without actually trimming out resistor's value of a resistor. The invention also allows design of thermal isolation to minimize or optimize resistance variation of the overall compound resistance.