SN54/74LS83A
FUNCTIONAL DESCRIPTION
The LS83A adds two 4-bit binary words (A plus B) plus the incoming carry. The binary sum appears on the sum outputs (∑ –∑ )
1
4
and outgoing carry (C ) outputs.
4
C + (A +B )+2(A +B )+4(A +B )+8(A +B ) = ∑ +2∑ +4∑ +8∑ +16C
4
0
1
1
2
2
3
3
4
4
1
2
3
4
Where: (+) = plus
Due to the symmetry of the binary add function the LS83A can be used with either all inputs and outputs active HIGH (positive
logic) or with all inputs and outputs active LOW (negative logic). Note that with active HIGH Inputs, Carry Input can not be left open,
but must be held LOW when no carry in is intended.
Example:
C
A
1
A
2
A
3
A
4
B
1
B
2
B
3
B
4
∑
∑
∑
∑
C
4
0
1
2
3
4
Logic Levels
Active HIGH
Active LOW
L
L
H
L
H
H
L
L
H
H
H
L
L
H
0
1
0
1
1
0
0
1
1
0
1
0
0
1
0
1
1
0
1
0
1
0
0
1
0
1
1
0
(10+9 = 19)
(carry+5+6 = 12)
Interchanging inputs of equal weight does not affect the operation, thus C , A , B , can be arbitrarily assigned to pins 10, 11,
0
1
1
13, etc.
FUNCTIONAL TRUTH TABLE
C (n–1)
A
n
B
n
∑
C
n
n
L
L
L
L
L
L
L
L
H
H
L
L
H
H
H
L
H
L
H
L
H
H
H
L
H
L
L
L
H
L
H
H
H
L
H
H
H
H
L
H
C
C
C
— C are generated internally
3
1
0
4
— is an external input
— is an output generated internally
GUARANTEED OPERATING RANGES
Symbol
Parameter
Min
Typ
Max
Unit
V
CC
Supply Voltage
54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
T
A
Operating Ambient Temperature Range
54
74
–55
0
25
25
125
70
°C
I
I
Output Current — High
Output Current — Low
54, 74
–0.4
mA
mA
OH
54
74
4.0
8.0
OL
FAST AND LS TTL DATA
5-82
MOTOROLA [ MOTOROLA ]
