Cadence Virtuoso: Gmax & fmax of transistor

fmax is the maximum oscillation frequency of a transistor and one of its figure of merits.
Below this frequency, a transistor can provide power gain and can work as an amplifier. Above this frequency it cannot provide any gain. It can oscillate above fmax, hence it can be an oscillator. fmax is the frequency at which the maximum power gain of transistor is 1(0 dB).
This video shows how to find out fmax through s-parameter simulation in cadence virtuoso. It also shows how to plot Gmax of a transistor.
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[@rafaelperez3069]

Thanks! This was very useful!

[@tensorbundle]

welcome

[@alamgirhossain2013]

Thanks a lot. Sir, I have a question, How can we plot transconductance (gm) vs Frequency?

[@NaaJeevitham500]

What about the width and length of the transistor ?don't these values effect fmax?

[@GiorgiAptsiauriX]

Q: why don't you put just an inductor in series with the vgs source instead of the resistor? I mean what's the purpose of the resistor there? From what I've seen a traditional bias T with an inductor does the job. I simulated my transistor with an inductor, and it seems to be the same result.

[@nguyentienthanh405]

Sir, can you tell me where i can download the power transistor library and how to add it on Cadence?

[@tensorbundle]

Hello PDK library is not free. It must be supplied by a commercial Foundry. IC design and fabrication is an expensive process.

[@shupeishupei829]

this series of ic design using cadence virtuoso is helpful, could you upload more vidoes ?

[@tensorbundle]

Shupei Shupei Thanks for your appreciation. I will upload more.

[@nazlizargarpour1854]

Hi thanks for your nice and helpful video. Could you please explain about fT?

[@tensorbundle]

at fT the current gain of transistor is 0dB..This is the frequency below which we cannot use the MOSFET as amplifier due to loss of current gain

[@Ixedud]

​@@tensorbundleftmax is when maximum power gain (Gmax) of transistor is 1(0 dB). Ft is when current gain (h21) is 1(0 dB). Correct?

[@GiorgiAptsiauriX]

@@Ixedud Yes, it is correct.