LNA simulation using PSS

[nandsri]

hi,

since u guys were talking about PSS in Cadence for LNA simulation, can u tell me wat is the difference between the noise figure shown in PSS and the noise figure when i do a noise analysis. also which is the corect voltage gain(using PSS or ac analysis)?

thanx
sriram.

 

[bearing01]

PSS is sort-of a harmonic balance simulator. It is for large signal.

If you want to simulate the noise figure of the LNA with the presence of an out-of-band jammer then your PSS beat frequency would be the freq of the jammer. Then run pnoise and integrate the noise across your signal bandwidth out of the LNA and compare total integrated noise out to the noise out from the source. Use this to calculate noise figure. Then run a "noise" sim and compare your calculated NF to condition with a jammer.

F = total input referred noise / noise of source

(source noise voltage)^2 = 4KTR*BW

I do not use any of the PSS or SP built in functions to calculate NF. There is a chance that what it calculates isn't correct. This can be quite true for mixer simulations.

 

[nandsri]

hi again.

I am trying to simulate a single balanced mixer. Do you have any design steps that I should follow? Also what is the ideal conversion gain and noise figure that I should be aiming aty?
thanx for the help.

sriram.