Samsung Wingo S-2450, Service Manual

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Samsung Electronics 10-1
IC Internal Diagram
10. IC Internal Diagram
10-1 74HCT245 ; AUIC4
TLF5366
MM74HCT245
Octal
TRI-STATE
Transceiver
August 1996
MM74HCT245
Octal TRI-STATE
Transceiver
General Description
This TRI-STATE bi-directional buffer utilizes advanced sili-
con-gate CMOS technology and is intended for two-way
asynchronous communication between data buses( It has
high drive current outputs which enable high speed opera-
tion even when driving large bus capacitances( This circuit
possesses the low power consumption of CMOS circuitry*
yet has speeds comparable to low power Schottky TTL cir-
cuits(
This device is TTL input compatible and can drive up to 15
LS-TTL loads* and all inputs are protected from damage due
to static discharge by diodes to V
CC
and ground(
The MM74HCT245 has 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(
MM74HCT devices are intended to interface between TTL
and NMOS components and standard CMOS devices(
These parts are also plug-in replacements for LS-TTL devic-
es and can be used to reduce power consumption in exist-
ing designs(
Features
Y TTL input compatible
Y TRI-STATE outputs for connection to system busses
Y High output drive current9 6 mA (min)
Y High speed9 16 ns typical propagation delay
Y Low power9 80
m
A (74HCT Series)
Connection Diagram
Dual-In-Line Package
TLF5366 – 1
Top View
Order Number MM74HCT245
Truth Table
Control
Operation
Inputs
G DIR 245
L L B data to A bus
L H A data to B bus
H X isolation
H
e
high level L
e
low level* X
e
irrelevant
TRI-STATE is a registered trademark of National Semiconductor Corp(
C
1996 National Semiconductor Corporation RRD-B30M86Printed in U( S( A(
http9www(national(com