1.

General description

The 74HC283 is a high-speed Si-gate CMOS device and is pin compatible with low power

Schottky TTL (LSTTL). The 74HC283 is specified in compliance with JEDEC

standard no. 7A.

The 74HC283 adds two 4-bit binary words (An plus Bn) plus the incoming carry (CIN).

The binary sum appears on the sum outputs (S1 to S4) and the out-going carry (COUT)

according to the equation:

CIN + (A1 + B1) + 2(A2 + B2) + 4(A3 + B3) + 8(A4 + B4) =

= S1 + 2S2 + 4S3 + 8S4 + 16COUT

Where (+) = plus.

Due to the symmetry of the binary add function, the 74HC283 can be used with either all

active HIGH operands (positive logic) or all active LOW operands (negative logic). In case

of all active LOW operands the results S1 to S4 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 74HC583 for the BCD version.

2.

Features

−40 °Cto+80 °C and from −40 °C to +125 °C.

74HC283

4-bit binary full adder with fast carry

Rev. 03 — 11 November 2004

Product data sheet