Show me analysis statements and option statements for both Spectre and HSPICE.
I think analysis conditions are different even if you use HB analysis for both Spectre and HSPICE.
Yes, I do.You use exatrapolation point of Pin=-50dBm as post processing of Spectre results.
Do you use same value as post processing of HSPICE results ?
So, how can i be sure that results are valid?IIP3 is small signal distortion measure where Pin v.s. Pout is linear relation.
On the other hand, P1dB is essentially large signal drive distortion.
Same results are achieved with hp analysis like qpss in Spectre:Show me analysis statements and option statements for both Spectre and HSPICE.
I think analysis conditions are different even if you use HB analysis for both Spectre and HSPICE.
Show me analysis statements and option statements for both Spectre and HSPICE.1) simulation conditions for both Spectre and HSPICE are the same,
why results are different?
IIP3 is small signal distortion measure where Pin v.s. Pout is linear relation.2) why P-1dB is greater than IIP3
(in normal condition IIP3 is 10 to 15 dBm greater than P1dB)?
Conditions for HB Analyses are different.Spectre:
sweepqpss sweep param=Pin start=-50 stop=10 step=1 {
qpss qpss flexbalance=yes oversample=[1 1] funds=["f1" "f2"]
+ maxharms=[5 5] errpreset=conservative annotate=status
}
........................
HSPICE:
.HB tones=300e6,301e6 nharms=11 11 intmodmax=7
+SWEEP Pin:dBm -50.0 20 1.0
.HB tones=300e6,301e6 nharms=5 5 intmodmax=10
+SWEEP Pin:dBm -50.0 10 1.0
What do you want to mean ?So, how can i be sure that results are valid?
Set "intmodmax=22" for HSPICE.sweephb sweep param=Pin start=-50 stop=10 step=1 {
hb hb oversample=[1 1] fundfreqs=[freq1 freq2] maxharms=[11
+ 11] errpreset=conservative tstabOpt=yes annotate=status
I did as you suggested and results are as follows:Conditions for HB Analyses are different.
Change HSPICE like following.
Code:.HB tones=300e6,301e6 nharms=5 5 intmodmax=10 +SWEEP Pin:dBm -50.0 10 1.0
Set "intmodmax=22" for HSPICE.
Show me trace lines, 1st and 3rd using same tool.
I think you use Cadence Wavescan.
Plot Spectre and HSPICE results as over plot using Wavescan.
I mean, can i accept these results and report them, although I think that simulation conditions are standard and P1dB should be less than IIP3 by about 10 dBm! But, here IIP3 is less than P1dB! For me, results are strange.What do you want to mean ?
When distortion is dominant for input characteristics, IIP3 is larger than P1dBin.But, here IIP3 is less than P1dB!
For me, results are strange.
Excuse me, I am confused. Would you please explain some more or refer me to a reference or paper about this issue?!When distortion is dominant for input characteristics, IIP3 is larger than P1dBin.
However if distortion is fairly occupied by output characteristics, IIP3 could be lesser than P1dBin.
No.I sent results with the same tools as I used before.
No.
I don't have ViVa and Waveviewer, although i think no changes will be on results!No.
Plot Spectre results and HSPICE results using cadence ViVA or Sysnopsys Custom Waveviwer.
I looked for log files and find nothing. As I mentioned, I have used HSPICE version 2010 and Cadence version 6.14.No.
Both don't show version of simulator.
Show me version of simulator.
If you don't know how to know it, see logfile of simulator.
Yes, as I mentioned in my first post, the circuit has an active feedback. However, I have checked the stability of the LNA by means of K_stability_factor, which is greater than 1 in whole bandwidth (K_stab > 1 is a necessary and sufficient condition for the stability of a LNA).I think there is a feedback in the circuit.Have you ever checked the stability ?? If there is a stability issue, these results are valid at all.
Because P1dB Compression Point curve is pretty weird.
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