请问谁调过allen书上322页的亚阈值放大器

按说应该是第一级的增益应该是gmp/gmn，在亚阈值区约等于1，
但是调电路的时候，这个增益是-6db，这也太自小了吧....
看看参数，gmp=5+u，gmn=4+u
按公式也大于1了，怎么回事呢?请高手给讲一下吧
或者有没有人调过 ，第一级增益怎样才能到0db

看不到gm，贴图不要用bmp格式，给别人带来极大的麻烦

bias的问题

这个一直是困扰我的问题，能不能讲的详细一些呢?
先谢谢了

I don't know how did you test this circuit. You have not bias the output point (i.e. the drain connection point of PM4 and NM4), and need to isolate the ac signal of this point, that means using very large inductor to isolate the output and negative feedback input, and remembering to connect a very large capacitor to negative input, so you can get the correct gain.

恩 我把整体的图放上去了，但是一般二级运放输出级的漏不都是悬空的马?两个r0并联，增加输出阻抗，能设置成为一个定值吗?

Opam is used in the feedback loop, not using it under open loop condition, this is the main difference between opam and comparator. So we test it under the dc close loop, but measure the gain of its open loop, that is why we can not fix the negative input node, we should let it bias itself under the close loop, normally we use unit gain feedback to do it. Actually, the output of Opam seems floating, but it really not, since the close loop have bias it. Saying two parallel resistor to increase the output resistance, I don't know whether if it is your hand-error.

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