Current will be defined by high impedance and voltage by low impedance. So M2 decides the current. Current in the branch will be gm2*vin. Voltage will be defined by low impedance, so M1 defines the voltage at Vo. Current through M1 is gm2*vin, so VGS of M2 should be gm2*vin/gm1. vo comes out to be vin*(1-(gm2/gm1)). Gain will be 1-(gn2/gm1).
@anonymous-fp9og
Жыл бұрын
Can you explain how and why? By doing small signal I am getting it. But not by inspection
@RitayanMitraggmu
3 жыл бұрын
My approach: Considering only M1, it is a source follower. So vo1=vin. Considering only M2, it is a common source. So vo2=-gm2*(1/gm1)vin. By superposition, vo=vo1+vo2=(1-gm2/gm1) or, vo/vin=1-gm2/gm1=(gm1-gm2)/gm1
@vlsiorg
3 жыл бұрын
Now assume gm1=gm2 , the gain value would be interesting to note
@RitayanMitraggmu
3 жыл бұрын
@@vlsiorg Wow! Almost zero gain!
@rajkumarsah3124
2 жыл бұрын
for the 3rd circuit can we think it like this_ at small signal the current source will offer infinite resistance and will be open circuited .so Gm=gm/1+gmRs where Rs in infinite so Gm=0. And gain Av=-GmRd=0 ??
@Adgjmptw12able
2 жыл бұрын
GM of the overall circuit is gm1-gm2 Ro is 1/gm1 So, the gain is GmxRo
@goks_cool
2 жыл бұрын
So my approach was that, the drain current is same for both the MOSFETs. Assuming gm is same for both, and as Vg of both is same, then for current to be same, Vs should be equal for both the MOSFETs. Thus Vo becomes 0. Yeah if we assume gm1 & gm2 are different, then superposition approach yields better result.
@vlsiorg
3 жыл бұрын
Please assume gm1=gm2
@nishargshah4438
2 жыл бұрын
why is the gain not considering source degeneration resistance in gain calculation for the 4th circuit?
@vlsiorg
Жыл бұрын
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@mainakseal5027
Жыл бұрын
what will be the resistance as seen from above to downwards for 3rd problem ?
@balamatcha4797
2 жыл бұрын
Gain is 0 after assuming gm s are equal
@pavankori6986
2 жыл бұрын
gain = (ro1||ro2)
@chistiy9532
6 ай бұрын
dude speak english please 🙏
@vlsiorg
Ай бұрын
Sorry for the bad English. Will make it better in the next videos . Thanks for the feedback. Cheers
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