I've designed a clock subsystem that runs off a clipped sine wave oscillator. The oscillator itself has no enable pin; enable/disable is done by turning on/off the supply to the oscillator via an LDO. When the LDO is off, the oscillator is off, and the output of the oscillator is Hi-Z. This leads to the inverter oscillating about its resonant frequency due to Rf/Cf, a situation which burns power when the clock subsystem is supposed to be off.
Thus I need to switch power to the inverter on or off. The easiest way to do this is for me to switch ground, as I can use a low side NFET to switch ground to the inverter using the same logic as the EN to the LDO.
Question is: where dooes the decoupling cap go between when using a low side NFET is this fashion? Point #1 ( the GND pin of the inverter ) or #2 ( true ground point )? Does it matter? If it matters, why does it matter?
For reference schematic:
