Hi Shawn, I performed the suggestions you proposed. 1. I changed the simulation to not simulate with transient noise. I also changed from using a cds_thru instance to connect my vss net and the gnd! net to using a regular gnd symbol. This results in an even more simple circuit. In the logs, the max value achieved is now the same for both simulations (885.2 uA). the simulations are also done with conservative errpreset. 2. I was indeed measuring the ring oscillator's frequency with the frequency() function. Changing to the freq() function and looking to the frequency vs time there are no frequency transients. 3. The ring oscillator can not be tuned by a control voltage. It is just a ring of 51 inverters. For both simulations, an initial condition is set to one node to make the ring start oscillating immediately. I also have looked into the initial conditions files (spectre.ic) for both simulations which match almost exactly. Kind regards, Bjorn
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