A method for post-thermal-trimming annealing a thermally-trimmable resistor thermally-isolated on a substrate, the method comprising: trimming said thermally-trimmable resistor by applying a first power-measured signal to a heating resistor; and applying a second power-measured signal corresponding to a desired average annealing temperature to said heating resistor, wherein said second power-measured signal has a lower power level than said first power-measured signal.