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Diffstat (limited to 'Windows/spice/examples/Monte_Carlo/MC_ring.sp')
| -rw-r--r-- | Windows/spice/examples/Monte_Carlo/MC_ring.sp | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/Windows/spice/examples/Monte_Carlo/MC_ring.sp b/Windows/spice/examples/Monte_Carlo/MC_ring.sp new file mode 100644 index 00000000..58e5c141 --- /dev/null +++ b/Windows/spice/examples/Monte_Carlo/MC_ring.sp @@ -0,0 +1,251 @@ +Perform Monte Carlo simulation in ngspice +* 25 stage Ring-Osc. BSIM3 + +vin in out dc 0.5 pulse 0.5 0 0.1n 5n 1 1 1 +vdd dd 0 dc 3.3 +vss ss 0 dc 0 +ve sub 0 dc 0 +vpe well 0 dc 3.3 + +.subckt inv1 dd ss sub well in out +mn1 out in ss sub n1 w=2u l=0.35u as=3p ad=3p ps=4u pd=4u +mp1 out in dd well p1 w=4u l=0.35u as=7p ad=7p ps=6u pd=6u +.ends inv1 + +.subckt inv5 dd ss sub well in out +xinv1 dd ss sub well in 1 inv1 +xinv2 dd ss sub well 1 2 inv1 +xinv3 dd ss sub well 2 3 inv1 +xinv4 dd ss sub well 3 4 inv1 +xinv5 dd ss sub well 4 out inv1 +.ends inv5 + +xinv1 dd ss sub well in out5 inv5 +xinv2 dd ss sub well out5 out10 inv5 +xinv3 dd ss sub well out10 out15 inv5 +xinv4 dd ss sub well out15 out20 inv5 +xinv5 dd ss sub well out20 out inv5 +xinv11 dd 0 sub well out buf inv1 +cout buf ss 0.2pF +* +.options noacct +.control + save buf $ we just need buf, save memory by more than 10x + let mc_runs = 10 $ number of runs for monte carlo + let run = 0 $ number of actual run + set curplot = new $ create a new plot + set curplottitle = "Transient outputs" + set plot_out = $curplot $ store its name to 'plot_out' + set curplot = new $ create a new plot + set curplottitle = "FFT outputs" + set plot_fft = $curplot $ store its name to 'plot_fft' + set curplot = new $ create a new plot + set curplottitle = "Oscillation frequency" + set max_fft = $curplot $ store its name to 'max_fft' + let mc_runsp = mc_runs + 1 + let maxffts = unitvec(mc_runsp) $ vector for storing max measure results + let halfffts = unitvec(mc_runsp)$ vector for storing measure results at -40dB rising +* +* define distributions for random numbers: +* unif: uniform distribution, deviation relativ to nominal value +* aunif: uniform distribution, deviation absolut +* gauss: Gaussian distribution, deviation relativ to nominal value +* agauss: Gaussian distribution, deviation absolut + define unif(nom, var) (nom + (nom*var) * sunif(0)) + define aunif(nom, avar) (nom + avar * sunif(0)) + define gauss(nom, var, sig) (nom + (nom*var)/sig * sgauss(0)) + define agauss(nom, avar, sig) (nom + avar/sig * sgauss(0)) +* +* We want to vary the model parameters vth0, u0, tox, lint, and wint +* of the BSIM3 model for the NMOS and PMOS transistors. +* We may obtain the nominal values (nom) by manually extracting them from +* the parameter set. Here we get them automatically and store them into +* variables. This has the advantage that you may change the parameter set +* without having to look up the values again. + set n1vth0=@n1[vth0] + set n1u0=@n1[u0] + set n1tox=@n1[tox] + set n1lint=@n1[lint] + set n1wint=@n1[wint] + set p1vth0=@p1[vth0] + set p1u0=@p1[u0] + set p1tox=@p1[tox] + set p1lint=@p1[lint] + set p1wint=@p1[wint] +* +* run the simulation loop + dowhile run <= mc_runs + * without the reset switch there is some strange drift + * towards lower and lower frequencies + reset + * run=0 simulates with nominal parameters + if run > 0 + altermod @n1[vth0]=gauss($n1vth0, 0.1, 3) + altermod @n1[u0]=gauss($n1u0, 0.05, 3) + altermod @n1[tox]=gauss($n1tox, 0.1, 3) + altermod @n1[lint]=gauss($n1lint, 0.1, 3) + altermod @n1[wint]=gauss($n1wint, 0.1, 3) + altermod @p1[vth0]=gauss($p1vth0, 0.1, 3) + altermod @p1[u0]=gauss($p1u0, 0.1, 3) + altermod @p1[tox]=gauss($p1tox, 0.1, 3) + altermod @p1[lint]=gauss($p1lint, 0.1, 3) + altermod @p1[wint]=gauss($p1wint, 0.1, 3) + end + tran 15p 50n 0 +* select stop and step so that number of data points after linearization is not too +* close to 8192, which would yield varying number of line length and thus scale for fft. +* +* We have to figure out what to do if a single simulation will not converge. +* Is there a variable which may be set if there is no convergence? +* Then we might skip this run and continue with a new run. It does not exist for now. +* So we have to rely on the robustness of the following steps not leading +* to a seg fault if the tran data are missing. +* + set run ="$&run" $ create a variable from the vector + set mc_runs ="$&mc_runs" $ create a variable from the vector + echo simulation run no. $run of $mc_runs + * save the linearized data for having equal time scales for all runs + linearize buf $ linearize only buf, no other vectors needed + set dt = $curplot $ store the current plot to dt (tran i+1) + setplot $plot_out $ make 'plt_out' the active plot + * firstly save the time scale once to become the default scale + if run=0 + let time={$dt}.time + end + let vout{$run}={$dt}.buf $ store the output vector to plot 'plot_out' + setplot $dt $ go back to the previous plot (tran i+1) + fft buf $ run fft on vector buf + let buf2=db(mag(buf)) + * find the frequency where buf has its maximum of the fft signal + meas sp fft_max MAX_AT buf2 from=0.1G to=0.7G + * find the frequency where buf is -40dB at rising fft signal + meas sp fft_40 WHEN buf2=-40 RISE=1 from=0.1G to=0.7G + * store the fft vector + set dt = $curplot $ store the current plot to dt (spec i) + setplot $plot_fft $ make 'plot_fft' the active plot + if run=0 + let frequency={$dt}.frequency + end + let fft{$run}={$dt}.buf $ store the output vector to plot 'plot_fft' + * store the measured value + setplot $max_fft $ make 'max_fft' the active plot + let maxffts[{$run}]={$dt}.fft_max + let halfffts[{$run}]={$dt}.fft_40 +* setplot $plot_out +* The following command does not work here. Why not? Probably not a real copy. +* destroy $dt $ save memory, we don't need this plot (spec) any more + setplot $dt $ go back to the previous plot + let run = run + 1 + end +***** plotting ********************************************************** +* plot {$plot_out}.allv + plot {$plot_out}.vout0 $ just plot the tran output with nominal parameters +* setplot $plot_fft +* plot db(mag(ally)) xlimit .1G 1G ylimit -80 10 + plot db(mag({$plot_fft}.ally)) xlimit .1G 1G ylimit -80 10 +* +* create a histogram from vector maxffts + setplot $max_fft $ make 'max_fft' the active plot + set startfreq=400MEG + set bin_size=5MEG + set bin_count=20 + compose xvec start=$startfreq step=$bin_size lin=$bin_count $ requires variables as parameters + settype frequency xvec + let bin_count=$bin_count $ create a vector from the variable + let yvec=unitvec(bin_count) $ requires vector as parameter + let startfreq=$startfreq + let bin_size=$bin_size + * put data into the correct bins + let run = 0 + dowhile run < mc_runs + set run = "$&run" $ create a variable from the vector + let val = maxffts[{$run}] + let part = 0 + * Check if val fits into a bin. If yes, raise bin by 1 + dowhile part < bin_count + if ((val < (startfreq + (part+1)*bin_size)) & (val > (startfreq + part*bin_size))) + let yvec[part] = yvec[part] + 1 + break + end + let part = part + 1 + end + let run = run + 1 + end + * plot the histogram + set plotstyle=combplot + plot yvec-1 vs xvec $ subtract 1 because with started with unitvec containing ones +* calculate jitter + let diff40 = (vecmax(halfffts) - vecmin(halfffts))*1e-6 + echo + echo Max. jitter is "$&diff40" MHz + rusage +.endc +******************************************************************************** +.model n1 nmos ++level=8 ++version=3.3.0 ++tnom=27.0 ++nch=2.498e+17 tox=9e-09 xj=1.00000e-07 ++lint=9.36e-8 wint=1.47e-7 ++vth0=.6322 k1=.756 k2=-3.83e-2 k3=-2.612 ++dvt0=2.812 dvt1=0.462 dvt2=-9.17e-2 ++nlx=3.52291e-08 w0=1.163e-6 ++k3b=2.233 ++vsat=86301.58 ua=6.47e-9 ub=4.23e-18 uc=-4.706281e-11 ++rdsw=650 u0=388.3203 wr=1 ++a0=.3496967 ags=.1 b0=0.546 b1=1 ++dwg=-6.0e-09 dwb=-3.56e-09 prwb=-.213 ++keta=-3.605872e-02 a1=2.778747e-02 a2=.9 ++voff=-6.735529e-02 nfactor=1.139926 cit=1.622527e-04 ++cdsc=-2.147181e-05 ++cdscb=0 dvt0w=0 dvt1w=0 dvt2w=0 ++cdscd=0 prwg=0 ++eta0=1.0281729e-02 etab=-5.042203e-03 ++dsub=.31871233 ++pclm=1.114846 pdiblc1=2.45357e-03 pdiblc2=6.406289e-03 ++drout=.31871233 pscbe1=5000000 pscbe2=5e-09 pdiblcb=-.234 ++pvag=0 delta=0.01 ++wl=0 ww=-1.420242e-09 wwl=0 ++wln=0 wwn=.2613948 ll=1.300902e-10 ++lw=0 lwl=0 lln=.316394 lwn=0 ++kt1=-.3 kt2=-.051 ++at=22400 ++ute=-1.48 ++ua1=3.31e-10 ub1=2.61e-19 uc1=-3.42e-10 ++kt1l=0 prt=764.3 ++noimod=2 ++af=1.075e+00 kf=9.670e-28 ef=1.056e+00 ++noia=1.130e+20 noib=7.530e+04 noic=-8.950e-13 +**** PMOS *** +.model p1 pmos ++level=8 ++version=3.3.0 ++tnom=27.0 ++nch=3.533024e+17 tox=9e-09 xj=1.00000e-07 ++lint=6.23e-8 wint=1.22e-7 ++vth0=-.6732829 k1=.8362093 k2=-8.606622e-02 k3=1.82 ++dvt0=1.903801 dvt1=.5333922 dvt2=-.1862677 ++nlx=1.28e-8 w0=2.1e-6 ++k3b=-0.24 prwg=-0.001 prwb=-0.323 ++vsat=103503.2 ua=1.39995e-09 ub=1.e-19 uc=-2.73e-11 ++rdsw=460 u0=138.7609 ++a0=.4716551 ags=0.12 ++keta=-1.871516e-03 a1=.3417965 a2=0.83 ++voff=-.074182 nfactor=1.54389 cit=-1.015667e-03 ++cdsc=8.937517e-04 ++cdscb=1.45e-4 cdscd=1.04e-4 ++dvt0w=0.232 dvt1w=4.5e6 dvt2w=-0.0023 ++eta0=6.024776e-02 etab=-4.64593e-03 ++dsub=.23222404 ++pclm=.989 pdiblc1=2.07418e-02 pdiblc2=1.33813e-3 ++drout=.3222404 pscbe1=118000 pscbe2=1e-09 ++pvag=0 ++kt1=-0.25 kt2=-0.032 prt=64.5 ++at=33000 ++ute=-1.5 ++ua1=4.312e-9 ub1=6.65e-19 uc1=0 ++kt1l=0 ++noimod=2 ++af=9.970e-01 kf=2.080e-29 ef=1.015e+00 ++noia=1.480e+18 noib=3.320e+03 noic=1.770e-13 +.end |