增益很小

航5

大家能否帮忙看一下这个轨到轨输出运算放大器，增益提不上去了，不知道是哪里的问题，在线等

航5

自己顶一下

航5

我这个是闭环增益，求助啊

LoktikVJ

Some substrates of n channel transistors are connected not to ground, do you use dip nwell?
You need to run a DC analysis, apply 0.5*vdd to inputs of OP AMP, and see states of all transistors and node voltages.  

LoktikVJ

Some substrates of n channel transistors are connected not to ground, do you use dip nwell?
You need to run a DC analysis, apply 0.5*vdd to inputs of OP AMP, and see states of all transistors and node voltages.  
It looks like current mirrors transistors are in linear mode. Or gm of input diff pairs has very low value.

LoktikVJ

Some substrates of n channel transistors are connected not to ground, do you use dip nwell?
You need to run a DC analysis, apply 0.5*vdd to inputs of OP AMP, and see states of all transistors and node voltages.  
It looks like current mirrors transistors are in linear mode. Or gm of input diff pairs has very low value.

LoktikVJ

Some substrates of n channel transistors are connected not to ground, do you use dip nwell?
You need to run a DC analysis, apply 0.5*vdd to inputs of OP AMP, and see states of all transistors and node voltages.  
It looks like current mirrors transistors are in linear mode. Or gm of input diff pairs has very low value.

航5

好的，我去尝试一下，thankyou

perfect_ic

静态工作点都不对吧

航5

共模输入为0的时候，管子都是饱和的，而且符合设定的值（这个是调整以后的），增益还是在40-50dB之间