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发帖数: 2 | 1 1) Without feedback, assume the impedance looking up at the source of M3 is
RD, then the impedance looking at the source of M3 is
Rin = (RD+Ro3)/(1+gm3*Ro3) = (RD+Ro3)/(gm3*Ro3)
2) M1 senses the Iout (Iout*RD) and feedback the current to input node gm1*
RD*Iout, loop gain T = gm1*RD
3) shunt feedback at the input --> Rin_eff = (RD+Ro3)/(gm3*Ro3*gm1*RD) (
ignore the 1+T factor)
4) Now look at the RD, 坑爹, depends on the load impedance:from the fig,
assume no loading,
RD = Rdsp || (gmn*Rdsn^2+Rds... 阅读全帖 |
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