DC-DC converter
.PARAM switchFreq = 10k
.PARAM dutyCycle = 0.5
V1 1 0 DC 5
V2 3 0 PULSE(0A 5A 0sec 0.01u 0.01u {dutyCycle/switchFreq} {1/switchFreq} )
L1 2 1 330u
*name, drain, gate, source, bulk, model
M1 2 3 4 4 IRF350
R1 4 0 20
D1 2 5 D1N4148
C1 5 0 1u
Robc 5 0 50k

.model IRF350 NMOS(Level=3
+Gamma=0 Delta=0 Eta=0 Theta=0 Kappa=0.2 Vmax=0 Xj=0
+Tox=100n Uo=600 Phi=.6 Rs=9.448m Kp=20.75u W=.73 L=2u Vto=3.234
+Rd=.2206 Rds=1.778MEG Cbd=2.206n Pb=.8 Mj=.5 Fc=.5 Cgso=9.529n
+Cgdo=178.5p Rg=3.531 Is=19.74p N=1 Tt=700n)

.MODEL D1N4148 D(IS=2.682N N=1.836 RS=.5664 IKF=44.17M XTI=3
+EG=1.11 CJO=4P M=.3333 VJ=.5 FC=.5 ISR=1.565N NR=2 BV=100
+IBV=100U TT=11.54N)

.STEP PARAM switchFreq LIST 100 1k 20k 100k
.TRAN 0.1 100M
.PROBE V(Robc)
.PROBE I(Robc)
.END