crystal oscillator simulation problem ..

elec_888

hello everybody im doing a crystal oscillator and simulating it using cadence ic6
my problem is when i use moderate transient accuracy the results show oscillation .. but when i use conservative transient simulation there is absolutely no oscillation in the results ! and no matter what the transient step is !! how can is solve this problem ?
thanks a lot

ralphtw

who know it ?!

specialest

Maybe  it doesn't oscillate.

r u using transient analysis? just try to give a initial current condition in inductance of the motional arm, and increase Cm (to decrease Q, thus the start up time will decrease.) make sure you gm is about 2~3X larger than calculated gmcrit.  and give it a long time transient. hundreds of usecond. and the maxstep also matters. set it to period/100 or less. then try it again.

you also should try PSS with shooting engin and oscic=linear (refer to the spectreRF user guide ). if it converges, check the one period waveform. that will be the stable waveform.

caltech_usa

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