HIT HD74HCT243, HD74HCT242 Datasheet
HD74HCT242/HD74HCT243
Quad. Bus Transceivers (with 3-state outputs)
Description
The HD74HCT242 is an inverting buffer and the HD74HCT243 is a noninverting buffer. Each device has
one active high enable (GBA), and one active low enable (GAB). GBA enables the A outputs and GAB
enables the B outputs.
The device does not have schmitt trigger inputs.
Features
• LSTTL Output Logic Level Compatibility as well as CMOS Output Compatibility
• High Speed Operation: tpd (A to Y) = 9.5 ns typ (CL = 50 pF)
• High Output Current: Fanout of 15 LSTTL Loads
• Wide Operating Voltage: VCC = 4.5 to 5.5 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
Function Table
HD74HCT242 HD74HCT243
Control Inputs Data Port Status Data Port Status
G
AB
HH O IOI
LHZZZZ
HLZZZZ
LL I O IO
I : Input
O : Output
O : Inverting Output
Z : High Impedance
G
BA
ABAB
HD74HCT242/HD74HCT243
(
)
Pin Arrangement
Block Diagram
HD74HCT242
GAB
NC
1A
2A
3A
4A
GND
1
2
3
4
5
6
7
14
13
12
11
10
V
CC
GBA
NC
1B
2B
3B
9
4B
8
Top view
V
CC
A
1 of 4
Transceivers
V
CC
B
GBA
GAB
2
HD74HCT243
A
GBA
GAB
Absolute Maximum Ratings
1 of 4
Transceivers
V
CC
HD74HCT242/HD74HCT243
V
CC
B
Item Symbol Rating Unit
Supply voltage range V
Input voltage V
Output voltage V
DC current drain per pin I
CC
IN
OUT
OUT
DC current drain per VCC, GND ICC, I
DC input diode current I
DC output diode current I
Power dissipation per package P
IK
OK
T
GND
–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
Storage temperature Tstg –65 to +150 °C
3
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