A 4-bit binary full adder in high-speed CMOS, SOIC-16, the arithmetic building block of discrete logic. It adds two 4-bit numbers (A0-A3 and B0-B3) plus a carry-in and produces a 4-bit sum (S0-S3) and a carry-out, with an internal fast (look-ahead) carry so the result settles quickly. Chain the carry-out of one into the carry-in of the next to add 8, 12, or more bits, and with a little logic on one operand it also subtracts. It is how counters, ALUs, and address arithmetic were built before microprocessors absorbed them. Runs 2-6 V.

Pinout

Pin	Name	Type	Function
1	S1	output	Sum bit 1 output. Bit 1 of the 4-bit binary sum of the A and B operands including the carry-in.
2	B1	input	Bit 1 of the B operand (4-bit binary addend). CMOS logic input.
3	A1	input	Bit 1 of the A operand (4-bit binary augend). CMOS logic input.
4	S0	output	Sum bit 0 (least-significant) output. Bit 0 of the 4-bit binary sum of the A and B operands including the carry-in.
5	A0	input	Bit 0 (least-significant) of the A operand (4-bit binary augend). CMOS logic input.
6	B0	input	Bit 0 (least-significant) of the B operand (4-bit binary addend). CMOS logic input.
7	CIN	input	Carry input. Carry from a lower-order adder stage; tie to GND when the SN74HC283 is used as the least-significant slice of a wider adder.
8	GND	power_in	Ground reference (0 V) for logic and supply currents.
9	COUT	output	Carry output. Carry generated from the four-bit addition; connects to the CIN of the next higher-order adder stage for cascaded expansion.
10	S3	output	Sum bit 3 (most-significant) output. Bit 3 of the 4-bit binary sum of the A and B operands including the carry-in.
11	B3	input	Bit 3 (most-significant) of the B operand (4-bit binary addend). CMOS logic input.
12	A3	input	Bit 3 (most-significant) of the A operand (4-bit binary augend). CMOS logic input.
13	S2	output	Sum bit 2 output. Bit 2 of the 4-bit binary sum of the A and B operands including the carry-in.
14	A2	input	Bit 2 of the A operand (4-bit binary augend). CMOS logic input.
15	B2	input	Bit 2 of the B operand (4-bit binary addend). CMOS logic input.
16	VCC	power_in	Positive supply voltage. HC types: 2 V to 6 V. HCT types: 4.5 V to 5.5 V. Bypass with a 0.1 uF ceramic capacitor to GND close to the pin.

Key specifications

Parameter	Value
Type	4-bit binary full adder
Adds	two 4-bit words + carry-in
Outputs	4-bit sum (S0-S3) + carry-out
Carry	internal look-ahead (fast)
Cascade	COUT to next CIN
Logic family	HC (high-speed CMOS)
Supply voltage	2-6 V
Package	SOIC-16

Ordering variants

Same part, different packaging or reel option.

CD74HC283M (SOIC-16, tube)
CD74HC283M96 (SOIC-16, tape & reel)

CAD (KiCad official)

Symbol: 74xx:74LS283 (pin-compatible with 74HC283)
Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
3D model: SOIC-16 (KiCad packages3D)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Texas Instruments datasheet (20 pp, sha256 3e7d71c958d64074, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF