FEATURES
· High-speed 4-bit binary addition
· Cascadable in 4-bit increments
· Fast internal look-ahead carry
· Output capability: standard
· ICC category: MSI

GENERAL DESCRIPTION
The 74HC/HCT283 are high-speed Si-gate CMOS devices
and are pin compatible with low power Schottky TTL
(LSTTL). They are specified in compliance with JEDEC
standard no. 7A.
The 74HC/HCT283 add two 4-bit binary words (An plus Bn)
plus the incoming carry. The binary sum appears on the
sum outputs (å1 to å4) and the out-going carry (COUT)
according to the equation:
CIN + (A1 + B1) + 2(A2 + B2) + +4(A3 + B3) + 8(A4 + B4) =
= å1 + 2å2 + 4å3 + 8å4 + 16COUT
Where (+) = plus.
Due to the symmetry of the binary add function, the “283”
can be used with either all active HIGH operands (positive
logic) or all active LOW operands (negative logic); see
function table. In case of all active LOW operands the
results å1 to å4 and COUT should be interpreted also as
active LOW. With active HIGH inputs, CIN must be held
LOW when no “carry in” is intended. Interchanging inputs
of equal weight does not affect the operation, thus CIN, A1,
B1 can be assigned arbitrarily to pins 5, 6, 7, etc.
See the “583” for the BCD version.