Hi analog2000,
Quote:In Ken Kundert's app note on switched cap noise, the clock amplitude is shown to be 0v
I am not familiar with the syntax of spectre. However, an example from Ken Kundert's
Simulating Switched-Capacitor Filters with SpectreRF is shown below. It is clear that the clocks Vphi1 and Vphi2 is not set to zero.
Code:Vphi1 (phi1 gnd) vsource type=pulse val0=VSS val1=VDD
+ period=CLOCK_PERIOD width=CLOCK_WIDTH
+ rise=CLOCK_TRANS fall=CLOCK_TRANS
+ delay=CLOCK_TRANS-CLOCK_PERIOD
+ fundname="clock"
Vphi2 (phi2 gnd) vsource type=pulse val0=VSS val1=VDD
+ period=CLOCK_PERIOD width=CLOCK_WIDTH
+ rise=CLOCK_TRANS fall=CLOCK_TRANS
+ delay=CLOCK_TRANS-CLOCK_PERIOD/2
+ fundname="clock"
// PSS analysis (sets periodic operating point)
clockAlone pss fund=CLOCK_FREQ saveinit=yes maxacfreq=6MHz \
writefinal="%C:r.ic" tstab=1.5ms swapfile="swap"
// Measure noise
unsmpldNoise (out gnd) pnoise start=100 stop=25kHz maxsideband=200
smpldNoise (out gnd) pnoise start=0_Hz stop=0.5*CLOCK_FREQ maxsideband=200 \
noisetype=timedomain noisetimepoints=[0] numberofpoints=1
Best regards,
Yawei