ET 发帖数: 10701 | 3 可这你没解释为啥amplifier transistor contribute more non-linearity呀。
你也说了,transconductance是nonlinearity source,
amplifier的transcondutance, gm = f(vgs, vth), 即使考虑short channel effect,
vds, gm = f(vgs, vth, vds)
对于既定的biasing point, vgs, vth look quite constant for me.
即使vgs, vth变化,那对gm的影响也是线性变化 (level -1 model).
从输入到输入的gain可近似为gm1/(gm2+gmb2) ,如果考虑body effect of cascode tr
ansistor,
而vout = gain * vin 即使vin是small signal sin. 如果gain是个常数,或者线性变化
的,vout的变化也是线性的。
对gm1/(gm2+gmb2) 求导,with respect to bias. 带来影响的我只 |
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