Untitled circuit

.Model PMOS pmos vto=-1.5
.MODEL NMOS NMOS VTO=1.5

.subckt Inverter IN OUT VDD GND
Mp OUT IN VDD VDD PMOS
MN OUT IN GND GND NMOS
.ENDS

XINV1  E NE VDD 0 INVERTER
Mp N1 NE VDD VDD PMOS

XINV2  IN OUT N1 N2 INVERTER
MN N2 E 0 0 NMOS


R1 VDD OUT 1E6
R2 OUT 0 1E6

VDD VDD 0 5
VE E 0 DC 5
VIN IN 0 DC 5 PULSE(0 5 0 0 0 2e-6 4e-6)