TL/F/6421
54LS283/DM54LS283/DM74LS283
4-Bit
Binary
Adders
with
Fast
Carry
June 1989
54LS283/DM54LS283/DM74LS283
4-Bit Binary Adders with Fast Carry
General Description
These full adders perform the addition of two 4-bit binary
numbers. The sum (R) outputs are provided for each bit and
the resultant carry (C4) is obtained from the fourth bit.
These adders feature full internal look ahead across all four
bits. This provides the system designer with partial look-
ahead performance at the economy and reduced package
count of a ripple-carry implementation.
The adder logic, including the carry, is implemented in its
true form meaning that the end-around carry can be accom-
plished without the need for logic or level inversion.
Features
Y
Full-carry look-ahead across the four bits
Y
Systems achieve partial look-ahead performance with
the economy of ripple carry
Y
Typical add times
Two 8-bit words 25 ns
Two 16-bit words 45 ns
Y
Typical power dissipation per 4-bit adder 95 mW
Y
Alternate Military/Aerospace device (54LS283) is avail-
able. Contact a National Semiconductor Sales Office/
Distributor for specifications.
Connection Diagram
Dual-In-Line Package
TL/F/6421–1
Order Number 54LS283DMQB, 54LS283FMQB, 54LS283LMQB,
DM54LS283J, DM54LS283W, DM74LS283M or DM74LS283N
See NS Package Number E20A, J16A, M16A, N16E or W16A
C
1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.