transistor sizing and transimpedance gain

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ricopt

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Can anyone tell me how W/L affect transimpedance gain ?
From my simulation result, If i increase W/L, transimpeance gain will decrease
Is it correct ?
is there any reference i can find ?
 

you can check this application note:

**broken link removed**

Hope this help

---------- Post added at 03:03 ---------- Previous post was at 02:58 ----------

Tell me what you are trying to do ? are you trying to design a transimpedance amplifier ?
 
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    ricopt

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What do you do with the L? For common source stage, the gain will depend on gm.ro. If you have same w and smaller L (though w/L is increased), gm will increase by a little while ro will be reduced more. And gm.ro might be smaller.
 
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    ricopt

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For L, i make it minimal 0.18um

---------- Post added at 15:53 ---------- Previous post was at 14:50 ----------
masa_2010 said:
you can check this application note:

**broken link removed**

Hope this help

---------- Post added at 03:03 ---------- Previous post was at 02:58 ----------

Tell me what you are trying to do ? are you trying to design a transimpedance amplifier ?
Click to expand...



Ya bro, doing transimpedance amplifier

---------- Post added at 15:55 ---------- Previous post was at 15:53 ----------
leo_o2 said:
What do you do with the L? For common source stage, the gain will depend on gm.ro. If you have same w and smaller L (though w/L is increased), gm will increase by a little while ro will be reduced more. And gm.ro might be smaller.
Click to expand...

Bro, what if i have the same L with 0.18 while i set my W=45 and 44, which one will have greater gain ?
 

If all other parameters are same, of cource bigger W will have bigger gain.
 

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