Circuits and methods that enable stacking of phase change material (PCM) switches and that accommodate variations in the resistance of the resistive heater(s) of such switches. Stacking is enabled by providing isolation switches for the resistive heater(s) in a PCM switch to reduce parasitic capacitance caused by the proximity of the resistive heater(s) to the PCM region of a PCM switch. Variations in the resistance of the resistive heater(s) of a PCM switch are mitigated or eliminated by sensing the actual resistance of the resistive heater(s) and then determining a suitable adjusted electrical pulse profile for the resistive heater(s) that generates a precise thermal pulse to the PCM region, thereby reliably achieving a desired switch state while extending the life of the resistive heater(s) and the phase-change material.