Full-Carry Look-Ahead Across the
Four Bits
Systems Achieve Partial Look-Ahead
Performance With the Economy of Ripple
Carry
Package Options Include Plastic
Small-Outline Packages, Ceramic Chip
Carriers, and Standard Plastic and Ceramic
300-mil DIPs

description
The ′F283 is a full adder that performs the addition
of two 4-bit binary words. The sum (Σ) outputs are
provided for each bit and the resultant carry (C4)
output is obtained from the fourth bit.
The device features full internal look-ahead
across all four bits generating the carry term C4 in
typically 5.7 ns. This capability 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. End-around carry
can be accomplished without the need for logic or
level inversion.
The ′F283 can be used with either all-active-high
(positive logic) or all-active-low (negative logic)
operands.
The SN54F283 is characterized for operation over
the full military temperature range of −55°C to
125°C. The SN74F283 is characterized for
operation from 0°C to 70°C.