HIT HD74HC243, HD74HC242 Datasheet
HD74HC242/HD74HC243
Quad. Bus Transceivers (with 3-state outputs)
Quad. Bus Transceivers (with noninverted 3-state outputs)
Description
The HD74HC242 is an inverting buffer and the HD74HC243 is a noninverting buffer. Each device has one
active high enable (GBA), and one active low enable (GAB). GBA enables the A output and GAB enables
the B outputs. The device does not have schmitt trigger inputs.
Features
• High Speed Operation: tpd = 10 ns typ (CL = 50 pF)
• High Output Current: Fanout of 15 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
Function Table
HD74HC242 HC74HC243
Control inputs Data Port Status Data Port Status
GAB GBA A B A B
HH O IOI
LHZZZZ
HLZZZZ
LL I O IO
I : Input
O : Output
O : Inverting Output
Z : Hight Impedance
HD74HC242/HD74HC243
(
)
(
)
Pin Arrangement
HD74HC242
HD74HC243
GAB
NC
1A
2A
3A
4A
GND
GAB
1
2
3
4
5
6
7
Top view
1
14
13
12
11
10
14
V
CC
GBA
NC
1B
2B
3B
9
4B
8
V
CC
2
NC
3
1A
4
2A
5
3A
6
4A
GND
2
7
Top view
13
12
11
10
GBA
NC
1B
2B
3B
9
4B
8
HD74HC242/HD74HC243
Absolute Maximum Ratings
Item Symbol Rating Unit
Supply voltage range V
Input voltage V
Output voltage V
DC current drain per pin I
DC current drain per VCC, GND ICC, I
DC input diode current I
DC output diode current I
Power Dissipation per package P
CC
IN
OUT
OUT
GND
IK
OK
T
Storage temperature Tstg –65 to +150 °C
Logic Diagram
HD74HC242
–0.5 to +7.0 V
–0.5 to VCC + 0.5 V
–0.5 to VCC + 0.5 V
±35 mA
±75 mA
±20 mA
±20 mA
500 mW
GBA
GAB
1 of 4
V
CC
Transceivers
A
V
CC
B
3
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