3 Input NAND GATE

Combinational Circuit Design and Simulation Using Gates

VCC, Power Supply Voltage• Voltage supplied to integrated circuit, Nominal VCC is +5V

ICCH, Power Supply Current • Supply current required to operate IC, Output logic is “1”

ICCL, Power Supply Current • Supply current required to operate IC, Output logic is “0”

IOS, Short Circuit Output Current • Amount of current TTL output circuit can deliver into S.C

IOL, Output Current Low • Maximum output terminal sink current, Output logic is “0”

IOH, Output Current High • Maximum output terminal source current, Output logic is “1”

IIH, Current Input High • Maximum current at input terminal, Input logic is “1”

Introduction to Digital Integrated Circuits

Combinational Circuit Design and Simulation Using Gates

IIL, Current Input Low• Maximum input current, Input voltage logic is “0”

VOL, Voltage Output Low • Maximum allowable output voltage, Output logic is “0”

VOH, Voltage Input High• Minimum output voltage, Output logic is “1”

VIH, Voltage Input High• Minimum logical 1 input voltage, VIH is 2 V

VIL, Voltage Input Low• Maximum logical 1 input voltage, VIL is 0.8 V

tpLH, Propagation delay time • From Output “Low” to “High”

tpHL, Propagation delay time • From Output “High” to “Low”

Introduction to Digital Integrated Circuits

Combinational Circuit Design and Simulation Using Gates

Introduction to Digital Integrated Circuits

Signal Delay Times

2 Input NAND(74xxx00) Parameter Values

Introduction to Digital Integrated Circuits

A.L=w’z+x’yz’

C.L=wx’y’z’

D.L=xy’z+w’z+x’yz’

E.L=z+x’y

B.L=xy’z’+x’yz

F.L=wx’y’+y’z

G.L=xy’z+w’

3 input NAND

4 input NAND

2 input NANDINV

Consider power consumption and switching speed P=(ICCave)(VCC), assume VCC=5 V

74LS00, 74LS10, 74LS20, and 74LS04

LD00 LS10 LS20 LS04ICCH 0.8mA 0.6mA 0.4mA

1.2mAICCL 2.4mA 1.8mA 1.2mA

3.6mAICCave 1.6mA 1.2mA 0.8mA

2.4mA Total average supply current is found

ICCave = 8(1.6)+6(1.2)+2(0.8)+6(2.4)=36mA

P=5.0V(36mA)=180mW

Introduction to Digital Integrated Circuits

Power Consumption Considerations