I am trying to simulate a switching mode PA with ELDO RF, and I am having trouble with convergence in certain process corners. Particularly in FAST process and FAST process/low temperature corners. Any ideas? I am using th e following options
Did you try with:
.option SST_CONVERGENCE_HELP=ADVANCED_NEWTON and sweep the input power with a small step (or use the SST_RAMPING_FACTOR=0.25, that is the same) ?
Maybe, being a switch PA, you need more time in process corner to stabilize the steady state, so use larger SST_TRAN_NPER
I hope it can help.
Mazz
1. I cannot get it coneverging with SST_CONVERGENCE_HELP=ADVANCED_NEWTON at all.
It will only converge (for some but not all corners) if I use SST_CONVERGENCE_HELP=TRANSIENT,
and I have to set the following option .option nomemstp (even to get convergence on the first point).
2. I tried increasin SST_TRAN_NPER to 20 with no success
Usually next step at this point is to contact Mentor support and send them your bench.
If the simulator does not reach the convergence, it can be because the switching mode PA have a long transient due to the switching. Did you have a check with transient? Do you know that you can use the transient result for sst (I don't remember the option...).
I hope it can help.
Mazz