请教2级运放补偿电容的估算

Just sim it.
there are many parasitcs poles/zeros if you have cascode etc.

just give the PM formulae ,you will understand it.

随便找本书，都有计算公式的

Thx, any suggestion about the value to start with?

Allen的模拟集成电路设计。里面有详细的推导过程。
Cc>0.22CL的前提条件是第二级的gm>10第一级的gm，需要达到的相位裕度是60度。

太感谢了，我找书来看看。因为我看的MARTIN的那本是说靠仿真,但我看到别人的设计一开始用到一些简单估算,所以想搞清楚是怎么回事.

This is interesting question. It really depends where the dominant pole
is located and then determine how to compensate the opamp.
Miller cap compensation should be used only for certain type of
design.
In Allen's book, Cc is around 20% of CL. This is based on the analysis
that 1st stage is dominant pole, and 2nd pole is out of GBW to get
either 45 or 60 degrees phase margin.

yup, I checked that chapter

如果第二级引入的极点是主极点，那么ALLEN书上讲的内容是不适用的，但一般来讲由于补偿电容对第一级来讲有密勒效应，因此第一级引入的极点一般都是主极点

进来学习一下！

对，谢谢

学习一下

先取1/2CL仿仿看

没有固定的方法，很多时候都是先根据经验雇一个值

2.2*gm1/gm2*CL

allen的书中有

xuexi

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