c1000
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Posts: 16

I'm trying to find a way in spectre to calculate the capacitance between every two terminals of a transistor (I hope it exists).
In Spectre users' Guide, info could be used to print nodetonode capacitance.
************************************************** ****************************** Inputsweep1 sweep param=dc dev=vg start=Vgnd stop=Vdd step=0.05 { Inputsweep2 dc param=dc dev=vd start=Vgnd stop=Vdd step=0.05 } sweepInfo info what=captab where=file file="capNodes" detail=nodetonode
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I expected I could get a capacitance list for every vd and vg combination,however unfortunately I just got the following text:
My questions are:
1: what's the meaning of 'n1:dbnode', 'n1:dbnode', and 'n2:dbnode'? I didn't have instance 'n2' inthe netlist...
2: how to get the nodetonode capacitances with respect to terminal voltages?
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****************************** 3 Capacitance Table `sweepInfo': 4 ****************************** 5 Capacitance values computed in info analysis `sweepInfo' at T = 27 C. 6 7 n2:dbnode : n1:dbnode fixed=0 , variable=53.4296 a , sum=53.4296 a . 8 n1:dbnode : 0 fixed=0 , variable=0 , sum=0 . 9 n1:dbnode : n1:int_b fixed=0 , variable=0 , sum=0 . 10 n1:dbnode : vd fixed=0 , variable=53.4296 a , sum=53.4296 a . 11 n1:dbnode : vss fixed=0 , variable=0 , sum=0 . 12 13 n1:int_b : n1:int_b fixed=576e21 , variable=8.87769 a , sum=9.45369 a . 14 n1:int_b : 0 fixed=0 , variable=0 , sum=0 . 15 n1:int_b : n1:dbnode fixed=0 , variable=0 , sum=0 . 16 n1:int_b : n1:int_g fixed=576e21 , variable=10.777 a , sum=11.353 a . 17 n1:int_b : n1:sbnode fixed=0 , variable=0 , sum=0 . 18 n1:int_b : vd fixed=0 , variable=423.98e21 , sum=423.98e21 . 19 n1:int_b : vg fixed=0 , variable=0 , sum=0 . 20 n1:int_b : vs fixed=0 , variable=1.47531 a , sum=1.47531 a . 21 n1:int_b : vss fixed=0 , variable=0 , sum=0 . 22 23 n1:int_g : n1:int_g fixed=53.6817 a , variable=91.0626 a , sum=144.744 a . 24 n1:int_g : 0 fixed=0 , variable=0 , sum=0 . 25 n1:int_g : n1:int_b fixed=576e21 , variable=247.452e21 , sum=823.452e21 . 26 n1:int_g : vd fixed=26.5528 a , variable=16.6791 a , sum=43.232 a . 27 n1:int_g : vg fixed=0 , variable=0 , sum=0 . 28 n1:int_g : vs fixed=26.5528 a , variable=74.136 a , sum=100.689 a . 29 30 n1:sbnode : n1:sbnode fixed=0 , variable=113.911 a , sum=113.911 a . 31 n1:sbnode : 0 fixed=0 , variable=0 , sum=0 . 32 n1:sbnode : n1:int_b fixed=0 , variable=0 , sum=0 . 33 n1:sbnode : vs fixed=0 , variable=113.911 a , sum=113.911 a . 34 n1:sbnode : vss fixed=0 , variable=0 , sum=0 . 35 36 vb : vb fixed=0 , variable=0 , sum=0 . 37 vb : 0 fixed=0 , variable=0 , sum=0 . 38 39 vd : vd fixed=26.5528 a , variable=72.2212 a , sum=98.774 a . 40 vd : 0 fixed=0 , variable=0 , sum=0 . 41 vd : n1:dbnode fixed=0 , variable=53.4296 a , sum=53.4296 a . 42 vd : n1:int_b fixed=0 , variable=3.45385 a , sum=3.45385 a . 43 vd : n1:int_g fixed=26.5528 a , variable=31.758 a , sum=58.3108 a . 44 vd : vg fixed=0 , variable=0 , sum=0 . 45 vd : vs fixed=0 , variable=16.4203 a , sum=16.4203 a . 46 47 vdd : vdd fixed=0 , variable=0 , sum=0 . 48 vdd : 0 fixed=0 , variable=0 , sum=0 . 49 50 vg : vg fixed=0 , variable=0 , sum=0 . 51 vg : 0 fixed=0 , variable=0 , sum=0 . 52 vg : n1:int_b fixed=0 , variable=0 , sum=0 . 53 vg : n1:int_g fixed=0 , variable=0 , sum=0 . 54 vg : vd fixed=0 , variable=0 , sum=0 . 55 vg : vs fixed=0 , variable=0 , sum=0 . 56 57 vs : vs fixed=26.5528 a , variable=170.151 a , sum=196.704 a . 58 vs : 0 fixed=0 , variable=0 , sum=0 . 59 vs : n1:int_b fixed=0 , variable=5.17639 a , sum=5.17639 a . 60 vs : n1:int_g fixed=26.5528 a , variable=48.5276 a , sum=75.0804 a . 61 vs : n1:sbnode fixed=0 , variable=113.911 a , sum=113.911 a .
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