MOS电容仿真方法

Alvin1234

电路设计或者后期FIB时，可能用到MOS管来构造电容，所以需要对电容值做个预估。分享一下MOS管构造电容的仿真方法:
NMOS为例，testbench搭建如下：（）一般可设置10u*10u的管子尺寸作为单位电容来参考）

                               
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对 vsin 源的参数设置为：AC Magnitude = 1/(2*3.1415926*f) V    Frequency = f Hz ， 一般可以直接设置 f=1Hz，AC Magnitude=1/(2*3.1415926)V；
仿真设置： ac仿真 在f=1Hz下，对 vsin 源进行 dc的参数扫描；
输出V0的电流，即为MOS电容的容值，见上图三。
原理解释：

                               
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%3CmxGraphModel%3E%3Croot%3E%3CmxCell%20id%3D%220%22%2F%3E%3CmxCell%20id%3D%221%22%20parent%3D%220%22%2F%3E%3CmxCell%20id%3D%222%22%20value%3D%22%24%24Uc%20%3D%20I%20*%20Rc%20%3D%20I%20*%20%5Cfrac%7B1%7D%7Bj*2*%5Cpi*f*C%7D%20%24%24%22%20style%3D%22text%3Bhtml%3D1%3Balign%3Dcenter%3BverticalAlign%3Dmiddle%3Bresizable%3D0%3Bpoints%3D%5B%5D%3Bautosize%3D1%3BstrokeColor%3Dnone%3BfillColor%3Dnone%3B%22%20vertex%3D%221%22%20parent%3D%221%22%3E%3CmxGeometry%20x%3D%22-20%22%20y%3D%22-682%22%20width%3D%22240%22%20height%3D%2230%22%20as%3D%22geometry%22%2F%3E%3C%2FmxCell%3E%3C%2Froot%3E%3C%2FmxGraphModel%3E%3CmxGraphModel%3E%3Croot%3E%3CmxCell%20id%3D%220%22%2F%3E%3CmxCell%20id%3D%221%22%20parent%3D%220%22%2F%3E%3CmxCell%20id%3D%222%22%20value%3D%22%24%24Uc%20%3D%20I%20*%20Rc%20%3D%20I%20*%20%5Cfrac%7B1%7D%7Bj*2*%5Cpi*f*C%7D%20%24%24%22%20style%3D%22text%3Bhtml%3D1%3Balign%3Dcenter%3BverticalAlign%3Dmiddle%3Bresizable%3D0%3Bpoints%3D%5B%5D%3Bautosize%3D1%3BstrokeColor%3Dnone%3BfillColor%3Dnone%3B%22%20vertex%3D%221%22%20parent%3D%221%22%3E%3CmxGeometry%20x%3D%22-20%22%20y%3D%22-682%22%20width%3D%22240%22%20height%3D%2230%22%20as%3D%22geometry%22%2F%3E%3C%2FmxCell%3E%3C%2Froot%3E%3C%2FmxGraphModel%3E%3CmxGraphModel%3E%3Croot%3E%3CmxCell%20id%3D%220%22%2F%3E%3CmxCell%20id%3D%221%22%20parent%3D%220%22%2F%3E%3CmxCell%20id%3D%222%22%20value%3D%22%24%24Uc%20%3D%20I%20*%20Rc%20%3D%20I%20*%20%5Cfrac%7B1%7D%7Bj*2*%5Cpi*f*C%7D%20%24%24%22%20style%3D%22text%3Bhtml%3D1%3Balign%3Dcenter%3BverticalAlign%3Dmiddle%3Bresizable%3D0%3Bpoints%3D%5B%5D%3Bautosize%3D1%3BstrokeColor%3Dnone%3BfillColor%3Dnone%3B%22%20vertex%3D%221%22%20parent%3D%221%22%3E%3CmxGeometry%20x%3D%22-20%22%20y%3D%22-682%22%20width%3D%22240%22%20height%3D%2230%22%20as%3D%22geometry%22%2F%3E%3C%2FmxCell%3E%3C%2Froot%3E%3C%2FmxGraphModel%3E得到

                               
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，所以电流波形即为电容波形。

kwankwaner

可以

小胡好好学习

+1，也可以AC Magnitude为1，f=0.159122