OCTAL BUS TRANSCEIVER - ST Microelectronics
Description
M74HCT245
OCTAL BUS TRANSCEIVER WITH 3 STATE OUTPUTS (NON INVERTED)
s HIGH SPEED: tPD = 13ns (TYP.
) at VCC = 4.
5V
s LOW POWER DISSIPATION: ICC = 4µA(MAX.
) at TA=25°C
s COMPATIBLE WITH TTL OUTPUTS : VIH = 2V (MIN.
) VIL = 0.
8V (MAX)
s SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 6mA (MIN)
s BALANCED PROPAGATION DELAYS: tPLH ≅ tPHL
s PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 245
DESCRIPTION
The M74HCT245 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 isolated.
DIP
SOP
TSSOP
ORDER CODES
PACKAGE
TUBE
T&R
DIP SOP TSSOP
M74HCT245B1R M74HCT245M1R M74HCT245RM13TR
M74HCT245TTR
All inputs are equipped with protection circuits against static discharge and transient excess voltage.
All floating bus terminals during High Z State must be held HIGH or LOW.
PIN CONNECTION AND IEC LOGIC SYMBOLS
August 2001
1/9
M74HCT245
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
NAME AND FUNCTION
Directional Control Data Inputs/Outputs
B1 to B8 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
DIR
L H X
FUNCTION
A BUS
OUTPUT INPUT Z
B BUS
INPUT OUTPUT
Z
OUTPUT
Yn A=B B=A
Z
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
VCC Supply Voltage
-0.
5 to +7
V
VI DC Input Voltage
-0.
5 to VCC + 0.
5
V
VO DC Output Voltage
-0.
5 to VCC + 0.
5
V
IIK DC Input Diode Current
± 20
mA
IOK DC Output Diode Current
± 20
mA
IO DC Output Current
± 35
mA
ICC or IGND DC VCC or Ground Current
± 70
mA
PD Power Dissipation
500(*)
mW
Tstg Storage Temperature
-65 to +150
°C
TL Lea...
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