jobless wrote on Sep 5th, 2006, 12:45pm:How to calculate the Q of the loaded Tank in a conventional differential LC VCO?
By adding in all the loads (devices and layout tracking) and including all the parasitic components (be R L or C)....
If you are wanting to do hand calculations, it'll be tough to get good accuarcy unless you have one dominant lossy component such as poor quality on chip inductor in conjunction with high Q other components (ie MIM caps, good varactors, FET capacitance cgs, cds etc..). If you want to know how to do LCR hand calculations, look it up in a book... i like Chris Bowick's RF Design as good intro into LCR calculations.