Hi,
I have a symmetric load 4 stage ring vco for simulation.Initially I try to simulate it by giving constant bias volatages at the PMOS bias and NMOS bias voltages. I do a transient analysis for observing the oscillation.But instead the simulation shows the two voltages stuck up at high (3.814V and 3.125V) for a 0.6um process.
pmos bias volatge is 0.5V and NMOS as 2.5V.
Thanks in advance,
V

Hi, Vijay,

I think that stuck is due to wrong bias. Do you bias the PMOS and NMOS using voltage source?

Please bias your ring VCO using a reference current, and generate the bias voltage for ring VCO using current mirror.


Best regards,
Yawei