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Design >> Analog Design >> A trivial question for Ken's paper SC-filters.pdf
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Message started by ethan on Jul 7^th, 2005, 10:34pm

Title: A trivial question for Ken's paper SC-filters.pdf
Post by ethan on Jul 7^th, 2005, 10:34pm

Hi everybody,

I have tried the examples in paper "Simulating Switched-Capacitor Filters with SpectreRF".

In the sc-filter netlist, the vin shows as following:

Vin (in gnd) vsource type=dc pacmag=1.0
+ ampl=INPUT_AMPL freq=INPUT_FREQ fundname="input"

But I have tried all the ways in my "vsource" setup for my own circuit, I either could get the following specification for two differential vsources:

V4 (Vin net082) vsource type=dc pacmag=500.0m pacphase=180
V1 (Vip net082) vsource type=dc pacmag=500.0m

or I could get:

V4 (Vin net082) vsource type=sine freq=10K ampl=500m sinephase=180 \
sinedc=2.5 pacmag=500.0m pacphase=180 fundname="input2"
V1 (Vip net082) vsource type=sine freq=10K ampl=500m sinedc=2.5 \

Then all of above netlists will work for PSS and PAC. Here is my question. I have run spectre in command line and open waveform with AWD(analog waveform display),
then in the sc-filter example, it displays:

|
|TFin-pac
scf.raw-Run1-|clockAlone-td.pss
|clockAlone-tran.pss
........

Then I found that through "clockAlone-tran.pss", I can get figure 10 bottom plot in paper page 19. But with my own circuit setup, after running spectre, I only can get

pss-fd.pss
pss-td.pss

I couldn't get "pss-tran.pss" for my own circuit.

Did anybody, by any chance, try and somhow get pss-tran.pss in his or her own circuit?

ethan

Title: Re: A trivial question for Ken's paper SC-filters.
Post by Ken Kundert on Jul 8^th, 2005, 12:14am

Set saveinit=yes on the PSS analysis to get the pss-tran.pss file.

-Ken