add example for capacitance

vdmos/IXTP6N100D2-cap.cir

@@ -0,0 +1,21 @@
+Test of VDMOS gate-source and gate-drain capacitance
+
+m1 d g s s IXTP6N100D2
+
+.MODEL IXTP6N100D2 VDMOS(KP=2.9 RS=0.1 RD=1.3 RG=1 VTO=-2.7 LAMBDA=0.03 CGDMAX=3000p CGDMIN=2p CGS=2915p TT=1371n a=1 IS=2.13E-08 N=1.564 RB=0.0038 m=0.548 Vj=0.1 Cjo=3200pF subthres=2.5m)
+
+vd d 0 dc 5
+vg g 0 pwl (0 -3 1 3)
+vs s 0 0
+vb b 0 0
+
+*.dc vd -0.7 100 0.05 vg -3 1 0.5
+
+.control
+save  all @m1[cgd] @m1[cgs]
+tran 1m 1
+plot vs#branch
+plot @m1[cgd] @m1[cgs]
+.endc
+
+.end