IM3 simulated by Hspice and spectre

[abcyin]

I simulate IM3 by pss analysis in spectre and .fft in Hspice , But the results are so different, the noise floor resulted by Hspice is much higher than the counterpart, about 20dB higher. Maybe my configuration in Hspice is wrong, but anybody can tell me which options I should use to lower noise floor.

my configuration:

.options converge=1 acct post list dcstep=2 probe

.tran 1n 21u

.fft v(outn,outp) start=1u stop=21u np=8192 fmin=10meg fmax=150meg

Best regards!

 

[mitgrace]

Excuse me , How do u apply two tone in Hspice , In spectre , it is easy to simulatr the IM3 , You can use PSS or Using two tone (Vsin) , Then Using FFT to check the two tone .

Example : 49M , 50M , check the two tone . The fft base is 1M ..



Thanks