#### akis

##### Junior Member level 1

I did the same thing but tpd failed again!Did you measure from rise=1 to rise=2 , and from fall=1 to fall=2 ?

This is anon-invertinggate, so you have to measure propagation delay times from first rise to second rise, resp. from first fall to second fall:

.measure tpdr

+ trig v(c1) val='supply/2' rise=1

+ targ v(d1) val='supply/2' rise=2

.measure tpdf

+ trig v(c1) val='supply/2' fall=1

+ targ v(d1) val='supply/2' fall=2

Any idea?

Now for fanOut 2 to 5 i have to add the gates at the output of 3rd stage. Right?

And is it necessary to run every simulation(for fanout 1...5) 5 separate times?

Or i have to add code like this:

Vdd VDD VSS 'SUPPLY'

Vin A1 VSS=0 PULSE 0 'SUPPLY' 0ps 20ps 20ps 120ps 200ps

X1 A1 B1 VDD VSS INV_X1

X2 B1 C1 VDD VSS INV_X1

X3 C1 D1 VDD VSS INV_X1 m=fanout

X4 D1 E1 VDD VSS INV_X1

x5 E1 F1 VDD VSS INV_X1

.TRAN 1ps 200ps START=0ps sweep fanout 1 5 1

run this simulation but tpd was not rising every time(sometimes was falling).

here are the results:

tpdr= 1.1483E-11 targ= 1.8176E-10 trig= 1.7028E-10

tpdf= 7.4110E-12 targ= 3.5720E-11 trig= 2.8309E-11

tpd= 9.4470E-12

*** parameter fanout = 2.000E+00 ***

tpdr= 1.0593E-11 targ= 1.8298E-10 trig= 1.7239E-10

tpdf= 7.0239E-12 targ= 3.9184E-11 trig= 3.2160E-11

tpd= 8.8085E-12

*** parameter fanout = 3.000E+00 ***

tpdr= 1.0810E-11 targ= 1.8503E-10 trig= 1.7422E-10

tpdf= 6.6195E-12 targ= 4.3182E-11 trig= 3.6562E-11

tpd= 8.7147E-12

*** parameter fanout = 4.000E+00 ***

tpdr= 1.1117E-11 targ= 1.8717E-10 trig= 1.7606E-10

tpdf= 6.5845E-12 targ= 4.7403E-11 trig= 4.0819E-11

tpd= 8.8509E-12

*** parameter fanout = 5.000E+00 ***

tpdr= 1.1337E-11 targ= 1.8913E-10 trig= 1.7779E-10

tpdf= 6.1490E-12 targ= 5.1560E-11 trig= 4.5411E-11

tpd= 8.7428E-12

meas_variable = tpdr

mean = 11.0680p varian = 1.347e-25

sigma = 367.0738f avgdev = 293.1873f

max = 11.4830p min = 10.5931p

meas_variable = tpdf

mean = 6.7576p varian = 2.293e-25

sigma = 478.8820f avgdev = 367.9152f

max = 7.4110p min = 6.1490p

meas_variable = tpd

mean = 8.9128p varian = 9.205e-26

sigma = 303.3963f avgdev = 213.6820f

max = 9.4470p min = 8.7147p