Hi all,

I just got a new PDK, so i decided to test an old LNA circuit using the new PDK. The gain and noise seemed to be fine, but there is a problem with IIP3. I ran both the PSS and PAC analysis. I set the PSS analysis to have one tone with frequency 2.45 GHz and amplitude prf where prf was swept from -80 dBm to -20 dBm (actually I tried sweeping several different ranges). For the PAC analysis, i set one tone with PAC magnitude = prf, and the frequency was set at absolute, 2.452 GHz.

I ran the simulation and found that the linear gain of the 2.452 GHz tone was -22 dB instead of +25 dB when plotted in the PAC form. I checked the PSS form, and plotted the linear gain for the 2.45 GHz signal and found it to be 25 dB as expected. Therefore, the problem is with the PAC analysis.

Anyway i've double and triple-checked everything, and have even gone back to the old PDK (which seems fine), but i can't isolate the problem. Does anybody know of the problem i'm speaking of and how to fix it?

thanks,
Aaron

thanks,


yeah it seems others were having the problem too, and we've contacted the foundry.


cheers,
Aaron