How to draw the IIP3 versus bias current in spectre?

[Bob WU]

Hello, everyone,

Currently I am designing an single-ended LNA, I have used PSS+PAC and
got the IP3, but how to draw the plot of IP3 versus bias current (or
other variables) in spectre? Thank you very much for helping a noob...

Best regards,
Bob

 

[Andrew Beckett]

Bob WU wrote, on 11/10/09 12:27:

Hello, everyone,

Currently I am designing an single-ended LNA, I have used PSS+PAC and
got the IP3, but how to draw the plot of IP3 versus bias current (or
other variables) in spectre? Thank you very much for helping a noob...

Best regards,
Bob

Hi Bob,

Sweep the variable for the bias current via the PSS form (rather than sweeping
input power - presuming you've got a good input power to measure the IP3 at,
there's no need to sweep it to measure IP3).

Then on the direct plot form, you can choose to measure the IPN - pick "Single
Point Input Power" and specify the input power. Choose to plot "Points". Select
the 3rd Order and 1st Order harmonic, and then plot - you'll get the IP3 versus
the swept variable.

Regards,

Andrew.