Designer’s Guide Community

‹ Previous topic | Next topic ›

Pages: 1

VerilogA apply transient final conditions to AC/noise analysis (Read 5342 times)

anamania

New Member

Offline

Posts: 2

VerilogA apply transient final conditions to AC/noise analysis
Jun 20^th, 2013, 7:49am

Hi,
I have built a VerilogA module that is the AGC for an analog PGA. At the end of transient analysis, the module sets the gain of the PGA so that the output swing settles to a target value whatever the input swing is. How do I apply this gain, says 5 bit control, to subsequent AC & noise analysis? I want to complete all analysis in one simulation.

Thanks.

IP Logged

Ken Kundert Global Moderator Offline Posts: 2384 Silicon Valley	Re: VerilogA apply transient final conditions to AC/noise analysis Reply #1 - Jun 21^st, 2013, 6:24am Try setting restart=no on the AC analysis, and make sure it is run after the transient analysis. -Ken
Back to top	IP Logged

weber8722 Community Member Offline Posts: 95	Re: VerilogA apply transient final conditions to AC/noise analysis Reply #2 - Mar 1^st, 2015, 11:06am Hi Ken, can you give a short example spectre netlist. I think this question is often asked. In Cadence I typically solve the problem with ADEXL and calcVal, but a pure spectre solution would be much more elegant! Bye Stephan
Back to top	IP Logged

Ken Kundert

Global Moderator

Offline

Posts: 2384
Silicon Valley

Re: VerilogA apply transient final conditions to AC/noise analysis
Reply #3 - Mar 1^st, 2015, 12:01pm

Code:

// Test case where the AC analysis that follows a transient uses the operating
// point from the final point of the transient analysis.

simulator lang=spectre

Vin (in 0) vsource type=pulse val0=0 val1=1 mag=1
R   (in d) resistor r=1k
D   (d  0) dmod
model dmod diode

ACpre ac start=1 stop=1M
TR tran stop=1u
ACpost ac start=1 stop=1M prevoppoint=yes

IP Logged

Pages: 1

‹ Previous topic | Next topic ›