promach
Advanced Member level 4
For transconductance measurement of a CMOS inverter, I am getting real and imaginary results for Gm (third and fourth column of Transconductance_of_CMOS_inverter.log). Why ?
CMOS_inverter.net
test_CMOS_inverter.net
Transconductance_of_CMOS_inverter.log
CMOS_inverter.net
Code:
* gnetlist -L ../.. -g spice-noqsi -o CMOS_Inverter.net CMOS_Inverter.sch
* SPICE file generated by spice-noqsi version 20170819
* Send requests or bug reports to [email]jpd@noqsi.com[/email]
.subckt INV1 2 1
*
M4 1 2 Vdd Vdd P1 l=0.4u w=3u m=25
M1 1 2 Vss Vss N1 l=1.2u w=3u m=25
*
.ENDS
test_CMOS_inverter.net
Code:
* gnetlist -L ../.. -g spice-noqsi -o test_CMOS_Inverter.net test_CMOS_Inverter.sch
* SPICE file generated by spice-noqsi version 20170819
* Send requests or bug reports to [email]jpd@noqsi.com[/email]
X1 Vin 2 INV1
Vs Vss GND 0V
Vin Vin GND AC 1
Vd Vdd GND 'SUPPLY'
V_IP_out 2 1 DC 0V
Cout GND 1 1n
.PARAM SUPPLY=3.3v
.options TEMP=25
.MODEL n1 NMOS
.MODEL p1 PMOS
.GLOBAL Vdd Vss
.INCLUDE CMOS_Inverter.net
.control
ac lin 100 1 10G
let Gm=(i(v_ip_out))/Vin
plot Gm
print Gm > Transconductance_of_CMOS_inverter.log
.endc
Transconductance_of_CMOS_inverter.log
Code:
* gnetlist -l ../.. -g spice-noqsi -o test_cmos_inverter.net test_cmos_inverter.sch
AC Analysis Sun Mar 4 10:09:16 2018
--------------------------------------------------------------------------------
Index frequency gm
--------------------------------------------------------------------------------
0 1.000000e+00 3.578308e-24, 7.113253e-18
1 1.010101e+08 1.413483e-11, 2.781739e-13
2 2.020202e+08 1.413894e-11, 1.391274e-13
3 3.030303e+08 1.413970e-11, 9.275656e-14
4 4.040404e+08 1.413996e-11, 6.956873e-14
5 5.050505e+08 1.414009e-11, 5.565547e-14
6 6.060606e+08 1.414015e-11, 4.637978e-14
7 7.070707e+08 1.414020e-11, 3.975421e-14
8 8.080808e+08 1.414022e-11, 3.478500e-14
9 9.090909e+08 1.414024e-11, 3.092004e-14
10 1.010101e+09 1.414025e-11, 2.782806e-14
11 1.111111e+09 1.414026e-11, 2.529825e-14
12 1.212121e+09 1.414027e-11, 2.319008e-14
13 1.313131e+09 1.414027e-11, 2.140623e-14
14 1.414141e+09 1.414028e-11, 1.987722e-14
15 1.515152e+09 1.414028e-11, 1.855208e-14
16 1.616162e+09 1.414029e-11, 1.739258e-14
17 1.717172e+09 1.414029e-11, 1.636949e-14
18 1.818182e+09 1.414029e-11, 1.546007e-14
19 1.919192e+09 1.414029e-11, 1.464639e-14
20 2.020202e+09 1.414029e-11, 1.391407e-14
21 2.121212e+09 1.414029e-11, 1.325150e-14
22 2.222222e+09 1.414030e-11, 1.264916e-14
23 2.323232e+09 1.414030e-11, 1.209919e-14
24 2.424242e+09 1.414030e-11, 1.159506e-14
25 2.525253e+09 1.414030e-11, 1.113126e-14
26 2.626263e+09 1.414030e-11, 1.070313e-14
27 2.727273e+09 1.414030e-11, 1.030672e-14
28 2.828283e+09 1.414030e-11, 9.938626e-15
29 2.929293e+09 1.414030e-11, 9.595915e-15
30 3.030303e+09 1.414030e-11, 9.276051e-15
31 3.131313e+09 1.414030e-11, 8.976824e-15
32 3.232323e+09 1.414030e-11, 8.696298e-15
33 3.333333e+09 1.414030e-11, 8.432774e-15
34 3.434343e+09 1.414030e-11, 8.184752e-15
35 3.535354e+09 1.414030e-11, 7.950902e-15
36 3.636364e+09 1.414030e-11, 7.730044e-15
37 3.737374e+09 1.414030e-11, 7.521124e-15
38 3.838384e+09 1.414030e-11, 7.323199e-15
39 3.939394e+09 1.414030e-11, 7.135425e-15
40 4.040404e+09 1.414030e-11, 6.957040e-15
41 4.141414e+09 1.414030e-11, 6.787356e-15
42 4.242424e+09 1.414030e-11, 6.625752e-15
43 4.343434e+09 1.414030e-11, 6.471665e-15
44 4.444444e+09 1.414030e-11, 6.324582e-15
45 4.545455e+09 1.414030e-11, 6.184036e-15
46 4.646465e+09 1.414030e-11, 6.049600e-15
47 4.747475e+09 1.414030e-11, 5.920885e-15
48 4.848485e+09 1.414030e-11, 5.797534e-15
49 4.949495e+09 1.414030e-11, 5.679217e-15
50 5.050505e+09 1.414030e-11, 5.565632e-15
51 5.151515e+09 1.414030e-11, 5.456502e-15
52 5.252525e+09 1.414030e-11, 5.351570e-15
53 5.353535e+09 1.414030e-11, 5.250597e-15
54 5.454545e+09 1.414030e-11, 5.153363e-15
Index frequency gm
--------------------------------------------------------------------------------
55 5.555556e+09 1.414031e-11, 5.059666e-15
56 5.656566e+09 1.414031e-11, 4.969315e-15
57 5.757576e+09 1.414031e-11, 4.882134e-15
58 5.858586e+09 1.414031e-11, 4.797959e-15
59 5.959596e+09 1.414031e-11, 4.716638e-15
60 6.060606e+09 1.414031e-11, 4.638027e-15
61 6.161616e+09 1.414031e-11, 4.561994e-15
62 6.262626e+09 1.414031e-11, 4.488413e-15
63 6.363636e+09 1.414031e-11, 4.417169e-15
64 6.464646e+09 1.414031e-11, 4.348150e-15
65 6.565657e+09 1.414031e-11, 4.281256e-15
66 6.666667e+09 1.414031e-11, 4.216388e-15
67 6.767677e+09 1.414031e-11, 4.153457e-15
68 6.868687e+09 1.414031e-11, 4.092377e-15
69 6.969697e+09 1.414031e-11, 4.033067e-15
70 7.070707e+09 1.414031e-11, 3.975452e-15
71 7.171717e+09 1.414031e-11, 3.919460e-15
72 7.272727e+09 1.414031e-11, 3.865023e-15
73 7.373737e+09 1.414031e-11, 3.812077e-15
74 7.474747e+09 1.414031e-11, 3.760563e-15
75 7.575758e+09 1.414031e-11, 3.710422e-15
76 7.676768e+09 1.414031e-11, 3.661600e-15
77 7.777778e+09 1.414031e-11, 3.614047e-15
78 7.878788e+09 1.414031e-11, 3.567713e-15
79 7.979798e+09 1.414031e-11, 3.522552e-15
80 8.080808e+09 1.414031e-11, 3.478520e-15
81 8.181818e+09 1.414031e-11, 3.435576e-15
82 8.282828e+09 1.414031e-11, 3.393679e-15
83 8.383838e+09 1.414031e-11, 3.352791e-15
84 8.484848e+09 1.414031e-11, 3.312877e-15
85 8.585859e+09 1.414031e-11, 3.273902e-15
86 8.686869e+09 1.414031e-11, 3.235833e-15
87 8.787879e+09 1.414031e-11, 3.198640e-15
88 8.888889e+09 1.414031e-11, 3.162291e-15
89 8.989899e+09 1.414031e-11, 3.126760e-15
90 9.090909e+09 1.414031e-11, 3.092018e-15
91 9.191919e+09 1.414031e-11, 3.058040e-15
92 9.292929e+09 1.414031e-11, 3.024800e-15
93 9.393939e+09 1.414031e-11, 2.992276e-15
94 9.494949e+09 1.414031e-11, 2.960443e-15
95 9.595960e+09 1.414031e-11, 2.929280e-15
96 9.696970e+09 1.414031e-11, 2.898767e-15
97 9.797980e+09 1.414031e-11, 2.868883e-15
98 9.898990e+09 1.414031e-11, 2.839609e-15
99 1.000000e+10 1.414031e-11, 2.810926e-15