SOA test for generic diode, including self-heating * forward direction * ngspice-35 .temp 100 vtamb tamb 0 27 v1 1 0 0.7 R1 1 0 100 ; just a parallel resistor Dth1 1 0 tj dmod1 thermal Rtj tj tamb 100 ; the thermal resistance junction to ambient * diode model parameters include all SOA parameters .model dmod1 d (rs=200m bv=21 rth0=1e6 tnom=25 fv_max=1.5 bv_max=20 id_max=1.5 pd_max=1 te_max=175) D2 1 0 dmod2 temp=125 * diode model parameters include all SOA parameters .model dmod2 d (rs=200m bv=21 rth0=100 tnom=25 fv_max=1.5 bv_max=20 id_max=1.5 pd_max=1 te_max=175) .option warn=1 maxwarns=2 .control save @dth1[id] @d2[id] all *dc v1 3 -22.5 -0.5 dc v1 0.02 2 0.02 *display set xbrushwidth=3 plot @dth1[id] @d2[id] loglog ylimit 10m 10 xlimit 0.1 1 settype temperature tj plot tj xlimit 0.5 1 ylimit 0 300 .endc .end