I'm currently trying to use the SPICE in spectre to measure the input capacitance of the inverter. However, from the output result in the log, it seems like the input capacitance might possibly not be presented in the way I expected, more specifically, what is m1:n1 representing in nmos? Why is there a fixed & variable for each capacitor? Please also include related documentation about the capacitance, thank you! Below is the spice code for the netlist in gpdk45nm library .param w_n=300n .param w_p=600n .param l_n=100n .param l_p=100n vvdd vdd 0 vdd vgnd gnd 0 0 M1 out11 in gnd gnd g45n1svt W=W_n L=l_n M2 out11 in vdd vdd g45p1svt W=W_p L=l_p .option CAPTAB=1 vin in gnd vdd Below is the output of the cap table. Capacitance values computed in info analysis `hspice_CaptabInfo' at T = 25 C. in : in fixed=0 , variable=0 , sum=0 . M1:int_d : M1:int_d fixed=40.98 a , variable=758.61 a , sum=799.59 a . M1:int_s : M1:int_s fixed=40.98 a , variable=591.135 a , sum=632.115 a . M2:int_d : M2:int_d fixed=89.4 a , variable=211.902 a , sum=301.302 a . M2:int_s : M2:int_s fixed=89.4 a , variable=340.435 a , sum=429.835 a . out11 : out11 fixed=0 , variable=0 , sum=0 . vdd : vdd fixed=0 , variable=645.373 a , sum=645.373 a . M1.n1 : M1.n1 fixed=81.96 a , variable=418.337 a , sum=500.297 a . M2.n1 : M2.n1 fixed=178.8 a , variable=172.953 a , sum=351.753 a .
↧