Hi all,

I recently perfomed mixed-mode simulation of a design containing both analog (schematic) and digital (verilog) section with AMS-Designer. I noted that the same transient simulation performed on a schematic containing only the analog section of the design takes more time with Spectre: the difference is huge, about 50% or maybe more!
The simulation is run on the same workstation and the simulation queue was empty in both cases.

I cannot explain how this may happen: I mean, as far as I know, AMSDesigner uses Spectre for the simulation of the analog part of the circuit!
Any ideas?

Thanks,
Cri

Hi Geoffrey,

the analog block drives a digital post-processing digital machine. Actually there is some feedback signal from the digital block to the analog core. Does it make difference?
In the analog-only simulation I simply delete the digital block and no post-processing is done: in this way the output analog data are raw and not corrected by the digital machine.

Thanks, bye!
Cri

Yes, I understand what you suppose about the "bad" bias point: it could be a possible reason. I am going to verify!
Thanks for your kind reply and regards,

Cri