BartlebyScrivener
Member level 5
- Joined
- Feb 8, 2012
- Messages
- 90
- Helped
- 0
- Reputation
- 0
- Reaction score
- 0
- Trophy points
- 1,286
- Activity points
- 2,081
Using transistor DC Operating Points in cadence
I have worked out that I can display a list of device parameters by clicking 'results>print>DC Operating point' and then clicking on the transistor I am interested in.
However, for my two stage amplifier, if I use the values of transconductance given to calculate the output resistance, and the resulting gain, I am getting a gain of 0.3.
Q2 - gm - 509.7×10-6 S
Q2 - ro - 1962 Ω
Q4 - gm - 296.4×10-6 S
Q4 - ro - 3374 Ω
Q7 - gm - 961.7×10-6 S
Q7 - ro - 1040 Ω
Q6 - gm - 904×10-6 S
Q6 - ro - 1106 Ω
AV = 509.7×10-6 × 961.7×10-6 S × 1241 × 535 = 0.3
But if I plot Vout / Vin I am getting 80dB
Why do the values not match up?
Thanks
- - - Updated - - -
I worked it out, I was using 1/gm when I should have been using 1/gds for the output resistance.
I have worked out that I can display a list of device parameters by clicking 'results>print>DC Operating point' and then clicking on the transistor I am interested in.
However, for my two stage amplifier, if I use the values of transconductance given to calculate the output resistance, and the resulting gain, I am getting a gain of 0.3.
Q2 - gm - 509.7×10-6 S
Q2 - ro - 1962 Ω
Q4 - gm - 296.4×10-6 S
Q4 - ro - 3374 Ω
Q7 - gm - 961.7×10-6 S
Q7 - ro - 1040 Ω
Q6 - gm - 904×10-6 S
Q6 - ro - 1106 Ω
AV = 509.7×10-6 × 961.7×10-6 S × 1241 × 535 = 0.3
But if I plot Vout / Vin I am getting 80dB
Why do the values not match up?
Thanks
- - - Updated - - -
I worked it out, I was using 1/gm when I should have been using 1/gds for the output resistance.
Last edited: