74640 Datasheet | National Semiconductor

Description These TRI-STATE bi-directional transceivers utilize advanced silicon-gate CMOS technology and are intended for two-way asynchronous munication between data buses They have high drive current outputs which enable high speed operation even when driving large bus capacitances These circuits possess the low power consumption of CMOS circuitry yet have speeds parable to low power Schottky TTL circuits All devices are TTL input patible and can drive up to 15 LS-TTL loads and all inputs are protected from damage due to static discharge by diodes to VCC and ground Both the MM54HCT640 MM74HCT640 and the MM54HCT643 MM74HCT643 have one active low enable input (G) and a direction control (DIR) When the DIR input is high data flows from the A inputs to the B outputs When DIR is low data flows from B to A The MM54HCT640 MM74HCT640 transfers inverted data from one bus to the other The MM54HCT643 MM74HCT643 transfers inverted data from the A bus to the B bus and non-inverted data from the B bus to the A bus MM54HCT MM74HCT devices are intended to interface between TTL and NMOS ponents and standard CMOS devices These parts are also plug-in replacements for LSTTL devices and can be used to reduce power consumption in existing designs Features Y TTL input patible Y Octal TRI-STATE outputs for m P bus applications 6 m A typical Y High speed 16 ns typical propagation delay Y Low power 80 m A maximum (74HCT) Connection Diagram Dual-In-Line Packages TL F 5370 - 1 Top View Order Number MM54HCT640 or MM74HCT640 TL F 5370 - 2 Top View Order Number MM54HCT643 or MM74HCT643 Truth Table Control Inputs Operation G DIR L L B data to A bus B data to A bus L H A data to B bus A data to B bus Isolation Isolation Hehigh level Lelow level Xeirrelevant TRI-STATE is a registered trademark of National Semiconductor Corp C1995 National Semiconductor Corporation TL F 5370 RRD-B30M105 Printed in U S A Absolute Maximum Ratings (Notes 1 2) If Military Aerospace...