CMOS INVERTER Vdd PMOS AB B A B 01 B=A 10 (a) Circuit symbol (b)Truth table (c) Boolean expression NMOS Vss= ground
11 A B Vss = Ground Vdd PMOS NMOS
NMOS AND PMOS TRANSISTORS NMOS Transistor PMOS Transistor VA=0 V=V VG=0V VG=0V Vd=ov Closed switch Closed switch Whenva=v WhenVG=Ov Connect source to drain when Connect source to drain whenvG=ov supply Vs: voltage at the source; VD: voltage at the drain; supp上 max voltage(aka a logical 1) Adapted from slides prepared (ground): min voltage(aka a logical O) by Hakim Weatherspoonof
• NMOS Transistor • Connect source to drain when VG = Vsupply VS = 0 V VG VG = VSupply VG = 0 V ▪PMOS Transistor • Connect source to drain when VG = 0 V VG VG = VSupply VG = 0 V VD VD = 0V Closed switch When VG = Vsupply Closed switch When VG = 0 V Vsupply VS = Vsupply Vsupply Vsupply VD VS : voltage at the source; VD: voltage at the drain; Vsupply: max voltage (aka a logical 1) (ground): min voltage (aka a logical 0) VD = Vsupply 12 Adapted from slides prepared by Hakim Weatherspoon of Cornell University
NMOS AND PMOS TRANSISTORS NMOS Transistor PMOS Transistor D D=0 S=V S=OV Closed switch Closed switch When VG=Vsupply WhenVG=0V Connect source to drain Connect source to drain when gate=1 when gate=o Vs: voltage at the source VD: voltage at the drain Adapted from slides prepared Vsupply max voltage (aka a logical f) by Hakim Weatherspoonof (ground): min voltage(aka a logical)
• NMOS Transistor • Connect source to drain when gate = 1 D S = 0V G G = 1 G = 0 ▪PMOS Transistor ▪ Connect source to drain when gate = 0 Vsupply D G G = 1 G = 0 D = 0 Closed switch When VG = Vsupply Closed switch When VG = 0 V S = Vsupply Vsupply Vsupply D = 1 VS : voltage at the source VD: voltage at the drain Vsupply: max voltage (aka a logical 1) (ground): min voltage (aka a logical 0) 13 Adapted from slides prepared by Hakim Weatherspoon of Cornell University
NAND GATS Vdd Vad A A BC out 001 B C 011 C=A·B (a) Circuit symbol (b) Truth table (c)Boolean expression Vss
A out Vdd B A B Vdd Vss 14
NOR GATS Vdd A A BC 001 A B C 010 C=A+B B 00 out 110 A (a) Circuit symbol (b) Truth table (c) Boolean expression
A out Vss Vdd B A B Vss 15