ft of a transistor - non existent in the documentation.

[AMSA84]

and now the S21
**broken link removed**

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Done, I posted before you answer My previous post.

 

[pancho_hideboo]

Try set m of MOS larger, e.g. m=20.

Anyway your MOS is not modeled well for RF.

Plot H21.
ft is a frequency of H21=0dB.

 

[AMSA84]

y21? I have ploted the S21 which was what you asked.

Do you really want the Y21? That would mean to reconfigure the testbench.

Gonna make the transistor bigger.

I don't know if you read, but I said that this mosfet is nota RF MOS but I want to know what's the range of frequencies that I can use this transistor. Do you know what I mean?

There is any other way to check at which extend the model can be used for high frequencies?

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What you mean by: "ft is a frequency of y21=0dB." ?

 

[pancho_hideboo]

Sorry. Not Y21.
H21 is correct.

Increase m of MOS, e.g. m=20 until S21 >> 0dB.

 

[AMSA84]

Okay. Gonna do that. H21? Or S21??

 

[pancho_hideboo]

Okay. Gonna do that. H21? Or S21??

Plot both.

 

[AMSA84]

Did as you suggested, m=20. Same thing.

 

[pancho_hideboo]

Did as you suggested, m=20. Same thing.

gm of your MOS is too small for evaluation of S21 and Gmax.

So increase m (Instance Multiplier) or Idrain.

 

[AMSA84]

I am not forcing Idrain. Should I use a current source? Doesnt make sense. So I just can increase the W Right?

I think I am gonna leave this and I'll try with a different design kit just for this purpose.

 

[pancho_hideboo]

https://www.designers-guide.org/Forum/YaBB.pl?num=1240322183/22#22

 

[AMSA84]

Nice. Gonna try tomorrow. I will come back tomorrow.

 

[pancho_hideboo]

"dcblock" and "dcfeed" are very common primitives in RF Simulator.
**broken link removed**
**broken link removed**

However introduction of these is faily recent in Cadence Spectre.

So you can use "analogLib/dcblock" and "analogLib/dcfeed".

Or use two sp2tswitch.
One is for gate.
The other is for drain.

I used "analogLib/sp2tswitch" in attached example.

You may use "analogLib/dcblock" and "analogLib/dcfeed"
instead of "analogLib/sp2tswitch".