hi guys,
need a little help with the attached circuit as im not sure why im able to get three different values of transconductance:
here's my evaluation so far:
- va = 1/λ, therefore λ=1/va leads to 1/10 = λ=0.1
- since we are given that Iss = 0.32, we know that since the transistors are matched evenly the current splits evenly, so Id = 0.16mA.
- ro = 1/λId = 62.5kΩ
- Id = 1/2μCoxW/L(Vgs-Vt)^2(1+Vds*λ)... we are given or know everything except Vgs and so we solve for that and get 0.879 V.
- Vov = Vgs - Vt = 0.179V
- The trouble starts when finding the transconductance, gm.
gm = μCoxW/L*Vov = sqrt(2*μCoxW/L*Id) = 2*Id/Vov
However, i'm getting three different values when i use those three equations -- any ideas? thanks in advance....
need a little help with the attached circuit as im not sure why im able to get three different values of transconductance:
here's my evaluation so far:
- va = 1/λ, therefore λ=1/va leads to 1/10 = λ=0.1
- since we are given that Iss = 0.32, we know that since the transistors are matched evenly the current splits evenly, so Id = 0.16mA.
- ro = 1/λId = 62.5kΩ
- Id = 1/2μCoxW/L(Vgs-Vt)^2(1+Vds*λ)... we are given or know everything except Vgs and so we solve for that and get 0.879 V.
- Vov = Vgs - Vt = 0.179V
- The trouble starts when finding the transconductance, gm.
gm = μCoxW/L*Vov = sqrt(2*μCoxW/L*Id) = 2*Id/Vov
However, i'm getting three different values when i use those three equations -- any ideas? thanks in advance....
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