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Design >> Analog Design >> Zero of a common source amplifier
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Message started by ram on Feb 24^th, 2004, 3:41am

Title: Zero of a common source amplifier
Post by ram on Feb 24^th, 2004, 3:41am

Hi,

I have a common source amp, with a pmos diode load. According to analysis zero should be at gm of input_transistor/cgd of input_transistor.

If cgd=cgdo*w; where cgdo=3.1500E-10 (from model file) and w=1u, cgd = 0.315 fF and if gm=97.7e-6, Zero should at 310.19 G rad/sec

But the star-hspice pz analysis shows a zero at 45.7 G rad/sec. I am not able to figure out the reason behind this difference. Can anybody please helpme with this.

Thanks and Regards
ram