Transient Analysis of an Inverter

As a final example, analyze the behavior of the simple MOS inverter shown in MOS Inverter Circuit.

Figure 2-4: MOS Inverter Circuit

1. Type the following netlist data into a file named quickINV.sp.

Inverter Circuit

.OPTIONS LIST NODE POST

.TRAN 200P 20N

.PRINT TRAN V(IN) V(OUT)

M1 OUT IN VCC VCC PCH L = 1U W = 20U

M2 OUT IN 0 0 NCH L = 1U W = 20U

VCC VCC 0 5

VIN IN 0 0 PULSE .2 4.8 2N 1N 1N 5N 20N

CLOAD OUT 0 .75P

.MODEL PCH PMOS LEVEL = 1

.MODEL NCH NMOS LEVEL = 1

.END

2. Type the following to run Star-Hspice.

hspice quickINV.sp > quickINV.lis

Use AvanWaves to examine the voltage waveforms at the inverter IN and OUT nodes. The waveforms are shown in Voltage at MOS Inverter Node 1 and Node 2.

Figure 2-5: Voltage at MOS Inverter Node 1 and Node 2