VCO cannot start up with NanoSim/Powermill?

[eejli]

I simulate the same LC VCO(2GHz) with hspice and smartSpice. The vco can start up without any .IC conditions. But when I use the same setup to powermill. The VCO cannot just oscillate. Anybody can help me on this. Thanks.

 

[cmos_dude]

I Think it is because of the Noise being taken into consideration while simulating.
I have used HSPICE and know that it takes noise considerations, which is why your VCO starts oscillating.But I cannot say how NanoSim/Powermill behave.

Please correct me if I am wrong.

Rgds
Cmos Dude

 

[eejli]

NanoSim actually can oscillate but oscillate to a different wrong frequency. That means NanoSim did start-up the oscillator.

 

[alenhan]

maybe u need to set voltage to a certain node

 

[cmos_dude]

maybe u need to set voltage to a certain node

This would mean that you are trying to initialize certain nodes of the VCO ????
But how would that be implemented in the real life situation, ie after fabrication ?

Regards
CMOS DUDE