LNA gain calculation in Spectre

[Maz]

Hi, a very basic question. I am trying to determine the gain of an
source degenerate LNA using Spectre. I understand gain is just the
Vout/Vin, however, since I am dealing with AC signals, when I try to
solve for the gain using the Spectre calculator, by doing
(average(Vout/Vin)) then trying to have the dBm value, I get infinity.
I can clearly see that my input signal is amplified when I do a
transient analysis, but just can't seem to determine the gain using the
calculator.

Any suggestions would be most appreciated.

Thanks.

 

[Andrew Beckett]

On 17 Feb 2006 21:39:00 -0800, "Maz" <maz.khorasani@gmail.com> wrote:

Hi, a very basic question. I am trying to determine the gain of an
source degenerate LNA using Spectre. I understand gain is just the
Vout/Vin, however, since I am dealing with AC signals, when I try to
solve for the gain using the Spectre calculator, by doing
(average(Vout/Vin)) then trying to have the dBm value, I get infinity.
I can clearly see that my input signal is amplified when I do a
transient analysis, but just can't seem to determine the gain using the
calculator.

Any suggestions would be most appreciated.

Thanks.

Are you doing an AC analysis? If so, why are you using "average"?

A few more details are really needed. What analyses are you doing, and what is
the exact expression you have in the calculator.

Regards,

Andrew.