M74HC643 - ST Microelectronics

M74HC643 OCTAL BUS TRANSCEIVER

The 74HC643 is an advanced high-speed CMOS OCTAL BUS TRANSCEIVER (3-STATE) fabricated with silicon gate C2MOS technology. This IC is intended for two-way asynchronous communication between data buses, and the direction of data transmission is determined by DIR input. The enable input G can be used to disable the device so that the buses are effectively isol.

Features

and transient excess voltage. PIN CONNECTION AND IEC LOGIC SYMBOLS August 2001 1/11 M74HC643 INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION PIN No 1 2, 3, 4, 5, 6, 7, 8, 9 18, 17, 16, 15, 14, 13, 12, 11 19 10 20 SYMBOL DIR A1 to A8 B1 to B8 NAME AND FUNCTION Directional Control Data Inputs/Outputs Data Inputs/Outputs G GND VCC Output Enable Input Ground (0V) Positive Supply Voltage TRUTH TABLE INPUTS G L L H X : Don’t Care Z : High Impedance FUNCTION DIR L H X A BUS OUTPUT INPUT Z B BUS INPUT OUTPUT Z OUTPUT Yn A=B B=A Z LOGIC DIAGRAM This logic diagram has not be used to esti.