Input Common Mode Swing

[kiat]

mode swing

hi all, i have a doubt on icms. with regard to that, we normally calculate the min and max swing by considering the conditions for the transistors in the input stage to be in the active region.

Does that mean the transistors at the later stage are also in the active region?

 

[elbadry]

could you please clarify your question?

 

[sunking]

no, it need not

 

[ezt]

Hi kiat.
I think we calculate all this input CM range to make our circuit work. which means, we want to calculate the range for which our circuit works. So I think, we always assume other next stages are doing their job. They are in active mode.

Regards,
EZT

 

[kiat]

thanks all for the ans...

hi ezt, so u mean we assume that if the input transistors are in saturation, the rest of the transistors will also follow? but it seems that it's not the case sometimes...

 

[gavinhu]

hi all, i have a doubt on icms. with regard to that, we normally calculate the min and max swing by considering the conditions for the transistors in the input stage to be in the active region.

Does that mean the transistors at the later stage are also in the active region?

i thank that input common mode swing is limit the input ac value, and the band swing can gain good work to make transistors in active region.

 

[isaacnewton]

Changing the input Commom Mode voltage at the input will not affect the biasing of later stages. So the transistors at the later stages should still work in the active region.

hi all, i have a doubt on icms. with regard to that, we normally calculate the min and max swing by considering the conditions for the transistors in the input stage to be in the active region.

Does that mean the transistors at the later stage are also in the active region?

 

[qqmz]

Changing the input Commom Mode voltage at the input will not affect the biasing of later stages. So the transistors at the later stages should still work in the active region.



your means is that the input stage and later stage should be seperately thought ,they are not related too much ?

 

[amarnath]

the input common mode range is simply the limit till which the transistors will operate linearly,ie in saturation,if the inputs exceed this value ,then obviously u are going to have non linear operation,so clipping may occur .

regards
amarnath