here is the HSPICE netlist from Michael Perrott diffamp (part of it)
Vsup vdd 0 vsupply
Vgnd gnd 0 0
Ibias vdd vd ibias ac 1u
.options post=1 delmax=5p relv=1e-6 reli=1e-6 relmos=1e-6 method=gear
.dc w 0.25u 100u 0.25u
.ac dec 1 1e1 1e2 sweep w 0.25u 100u 0.25u
.op
.probe dc lx7(M0) lx8(M0) i(M0)
.probe ac lx18(M0) lx19(M0) lx20(M0) lx21(M0) lx22(M0)
In the HSPICE, it save gm, gd0 in DC & save Cgs, Cgd, Cgb, Cdb in AC.
I try to do it in SPECTRE cadence...
however, those Cgs, Cgd information is not available in AC mode in spectre. Those value can be extracted in OP (DC) or OPT (transient). Are they the same?