nobody
|
Here is the second plot called "flip around SHA". The OTA used in the 1st and 2nd plot is the same. Given the gain of a OTA is A0 ,Cs = 2Cf, and input parasitic capacitance Cpi. Loop gain(1st) is A0*Cf/(Cs+Cf)= 1/3*A0 Loop gain(2nd) is expected to be A0*Cf/(Cf+Cpi). I can simulate the loop gain correctly in the 1st plot by using hspice but fail to get the loop gain in in the 2nd plot. I would like to konw what goes wrong. The ideal CMFB(VCCS) is added and ideal baluns are added to convert differential and common signals.
Thanks a lot.
|