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[Ngspice-users] .tran run twice: diferent results; why?
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From: Rui T. <rm...@un...> - 2010-03-10 18:00:16
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Hello, I've noticed something (strange): doing the same transient analysis on the same circuit, without changing nothing, I mean, executing "run" followed by "run" on the Ngspice prompt I get different transient initial solution, different circuit response, and different amount of data (No. of Data Rows). Transient setup: .tran 0.1ns 2ns 0.0 What causes this? Can I make it to "produce" the same result every time I do a "run", which means: every time I do a transient analysis ? Sincerely, Rui PS: Here is the Ngspice output: ****** ** ngspice-20 : Circuit level simulation program ** The U. C. Berkeley CAD Group ** Copyright 1985-1994, Regents of the University of California. ** Please submit bug-reports to: ngs...@li... ** Creation Date: Fri Feb 26 15:26:23 WET 2010 ****** Circuit: time step resposnse ngspice 1 -> Doing analysis at TEMP = 27.000000 and TNOM = 27.000000 No. of Data Rows : 1 Initial Transient Solution -------------------------- Node Voltage ---- ------- von2 0.4699 vcm2 0.4699 vop2 0.4699 vx 0 vin 0 vss 0 vod 0 xbn1.x1.x1 0 xbn1.x1.x2 0.4699 voc 0.4699 xbn1.x2.x1 0 xbn1.x2.x2 0.4699 xbn2.x1.x1 0 xbn2.x1.x2 0.5 vinpx 0.5 vcmi 0.5 xbn2.x2.x1 0 xbn2.x2.x2 0.5 vinnx 0.5 vinp 0.5 vinn 0.5 vdd 1.1 vcm1n 0.557146 vbb 0.0724063 vba 0.0724063 vcm1p 0.313324 vb2 0.132707 von1 0.509522 vop1 0.509522 va2 0.943802 va 0.955992 l.xbn2.x2.l2#branch 0 l.xbn2.x2.l1#branch 0 l.xbn2.x1.l2#branch -5.54934e-12 l.xbn2.x1.l1#branch 0 l.xbn1.x2.l2#branch -3.88972e-12 l.xbn1.x2.l1#branch 0 l.xbn1.x1.l2#branch 1.32556e-12 l.xbn1.x1.l1#branch 0 exn#branch 0 exp#branch 0 e1#branch 0 vvss#branch -2.06192e-11 vvdd#branch -0.000928776 vvcmi#branch -1.28253e-11 vvin#branch 0 No. of Data Rows : 63 ngspice 2 -> Doing analysis at TEMP = 27.000000 and TNOM = 27.000000 No. of Data Rows : 1 Initial Transient Solution -------------------------- Node Voltage ---- ------- von2 0.374225 vcm2 0.374225 vop2 0.374225 vx 5.00056e-20 vin 0 vss 0 vod -5.00056e-20 xbn1.x1.x1 -8.74318e-20 xbn1.x1.x2 0.374225 voc -6.74494e-23 xbn1.x2.x1 -1.25793e-20 xbn1.x2.x2 -6.74494e-23 xbn2.x1.x1 1.00011e-19 xbn2.x1.x2 1.35742e-16 vinpx 1.35742e-16 vcmi 0.5 xbn2.x2.x1 2.48911e-36 xbn2.x2.x2 0.5 vinnx -5.75875e-06 vinp 1.35742e-16 vinn -5.75875e-06 vdd 1.1 vcm1n 1.05073 vbb 1.05875e-06 vba 1.05892e-06 vcm1p 1.05113 vb2 0.310922 von1 0.69711 vop1 0.69711 va2 1.05118 va 0.697111 l.xbn2.x2.l2#branch 3.88804e-50 l.xbn2.x2.l1#branch 5.00056e-15 l.xbn2.x1.l2#branch 1.00021e-33 l.xbn2.x1.l1#branch -5.0005e-15 l.xbn1.x2.l2#branch -1.25806e-34 l.xbn1.x2.l1#branch -3.74262e-15 l.xbn1.x1.l2#branch -8.74406e-34 l.xbn1.x1.l1#branch 3.74262e-15 exn#branch 0 exp#branch 0 e1#branch -5.75933e-20 vvss#branch -9.33413e-12 vvdd#branch -0.000390532 vvcmi#branch -7.27596e-12 vvin#branch -5.75933e-20 No. of Data Rows : 68 ngspice 3 -> Warning: the following plots haven't been saved: tran2 selfias on time domain, Transient Analysis op2 selfias on time domain, Operating Point tran1 selfias on time domain, Transient Analysis op1 selfias on time domain, Operating Point Are you sure you want to quit (yes)? ngspice-20 done |