HIT HD74ACT280, HD74AC280 Datasheet
HD74AC280/HD74ACT280
9-bit Parity Generator/Checker
Description
The HD74AC280/HD74ACT280 is a high-speed parity generator/checker that accepts nine bits of input
data and detects whether an even or an odd number of these inputs is High. If an even number of inputs is
High, the Sum Even output is High. If an odd number is High, the Sum Even output is Low. The Sum Odd
output is the complement of the Sum Even output.
Features
• Outputs Source/Sink 24 mA
• HD74ACT280 has TTL-Cmpatible Inputs
Pin Arrangement
NC
ΣE
ΣO
GND
1
6
I
I7
2
3
8
I
4
5
6
7
(Top view)
14
13
12
11
10
CC
V
I5
I4
I3
I2
I1
9
I0
8
HD74AC280/HD74ACT280
Logic Symbol
I1I0
Pin Names
I2 I3 I5 I6 I7 I8I4
ΣO ΣE
I0 – I
O
E
Data Inputs
8
Odd Parity Output
Even Parity Output
Truth Table
Outputs
Number of High Inputs I
0, 2, 4, 6, 8 H L
1, 3, 5, 7, 9 L H
H : High Voltage Level
L : Low Voltage Level
0
– I
8
∑ Even ∑ Odd
2
Logic Diagram
HD74AC280/HD74ACT280
I8
I7 I6 I5 I4 I3 I2 I1 I0
ΣO ΣE
Please note that this diagram is provided only for the understanding of logic operations and should not be
used to estimate propagation delays.
3
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