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
I
6
1
I
7
2
NC 3
I
8
4
Σ
E
5
Σ
O
6
GND 7
(Top view)
14 V
CC
13 I
5
12 I
4
11 I
3
10 I
2
9 I
1
8 I
0
HD74AC280/HD74ACT280
Logic Symbol
I
0
I
1
I
2
I
3
I
4
I
5
I
6
I
7
I
8
Σ
O
Σ
E
Pin Names
I
0
– I
8
O
E
Data Inputs
Odd Parity Output
Even Parity Output
Truth Table
Outputs
Number of High Inputs I
0
– I
8
0, 2, 4, 6, 8
1, 3, 5, 7, 9
H :
L :
High Voltage Level
Low Voltage Level
∑
Even
H
L
∑
Odd
L
H
2
HD74AC280/HD74ACT280
Logic Diagram
I
8
I
7
I
6
I
5
I
4
I
3
I
2
I
1
I
0
Σ
O
Σ
E
Please note that this diagram is provided only for the understanding of logic operations and should not be
used to estimate propagation delays.
3
HD74AC280/HD74ACT280
DC Characteristics
(unless otherwise specified)
Item
Maximum quiescent supply current
Maximum quiescent supply current
Maximum I
CC
/input (HD74ACT280)
Symbol
I
CC
I
CC
I
CCT
Max
80
8.0
1.5
Unit
µA
µA
mA
Condition
V
IN
= V
CC
or ground, V
CC
= 5.5 V,
Ta = Worst case
V
IN
= V
CC
or ground, V
CC
= 5.5 V,
Ta = 25°C
V
IN
= V
CC
– 2.1 V, V
CC
= 5.5 V,
Ta = Worst case
AC Characteristics: HD74AC280
Ta = +25°C
C
L
= 50 pF
Item
Propagation delay
Symbol
t
PLH
V
CC
(V)*
1
3.3
5.0
Propagation delay
t
PHL
3.3
5.0
Note:
1. Voltage Range 3.3 is 3.3 V
±
0.3 V
Voltage Range 5.0 is 5.0 V
±
0.5 V
Min
1.0
1.0
1.0
1.0
Typ
14.5
11.0
14.5
11.0
Max
17.0
13.0
17.0
13.0
Ta = –40°C to +85°C
C
L
= 50 pF
Min
1.0
1.0
1.0
1.0
Max
18.5
14.5
18.5
14.5
ns
Unit
ns
AC Characteristics: HD74ACT280
Ta = +25°C
C
L
= 50 pF
Item
Propagation delay
Propagation delay
Note:
Symbol
t
PLH
t
PHL
V
CC
(V)*
1
5.0
5.0
Min
1.0
1.0
Typ
12.5
12.5
Max
15.0
15.0
Ta = –40°C to +85°C
C
L
= 50 pF
Min
1.0
1.0
Max
16.5
16.5
Unit
ns
ns
1. Voltage Range 5.0 is 5.0 V
±
0.5 V
Capacitance
Item
Input capacitance
Power dissipation capacitance
Symbol
C
IN
C
PD
Typ
4.5
60.0
Unit
pF
pF
Condition
V
CC
= 5.5 V
V
CC
= 5.0 V
4
Unit: mm
19.20
20.32 Max
14
8
6.30
7.40 Max
1
2.39 Max
1.30
7
7.62
0.51 Min
2.54 Min 5.06 Max
2.54
±
0.25
0.48
±
0.10
0.25
– 0.05
0° – 15°
+ 0.10
Hitachi Code
JEDEC
EIAJ
Weight (reference value)
DP-14
Conforms
Conforms
0.97 g
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