74LVC257AD from Nexperia, in a SOIC-16. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	S	input	Common data select input. LOW selects the nI0 inputs, HIGH selects the nI1 inputs, routed to the respective nY outputs. Schmitt-trigger CMOS input, 5.5 V tolerant.
2	1I0	input	Channel 1 data input from source 0. Routed to output 1Y when S is LOW and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
3	1I1	input	Channel 1 data input from source 1. Routed to output 1Y when S is HIGH and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
4	1Y	tri_state	Channel 1 3-state multiplexer output. Drives either 1I0 or 1I1 according to S; high-impedance when /OE is HIGH. Rated for 50 Ω transmission-line drive at 85 °C.
5	2I0	input	Channel 2 data input from source 0. Routed to output 2Y when S is LOW and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
6	2I1	input	Channel 2 data input from source 1. Routed to output 2Y when S is HIGH and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
7	2Y	tri_state	Channel 2 3-state multiplexer output. Drives either 2I0 or 2I1 according to S; high-impedance when /OE is HIGH. Rated for 50 Ω transmission-line drive at 85 °C.
8	GND	power_in	Ground reference (0 V). Connect to system ground.
9	3Y	tri_state	Channel 3 3-state multiplexer output. Drives either 3I0 or 3I1 according to S; high-impedance when /OE is HIGH. Rated for 50 Ω transmission-line drive at 85 °C.
10	3I1	input	Channel 3 data input from source 1. Routed to output 3Y when S is HIGH and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
11	3I0	input	Channel 3 data input from source 0. Routed to output 3Y when S is LOW and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
12	4Y	tri_state	Channel 4 3-state multiplexer output. Drives either 4I0 or 4I1 according to S; high-impedance when /OE is HIGH. Rated for 50 Ω transmission-line drive at 85 °C.
13	4I1	input	Channel 4 data input from source 1. Routed to output 4Y when S is HIGH and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
14	4I0	input	Channel 4 data input from source 0. Routed to output 4Y when S is LOW and /OE is LOW. Schmitt-trigger CMOS input, 5.5 V tolerant.
15	/OE	input	3-state output enable input, active LOW. When HIGH, all nY outputs are placed into the high-impedance state; when LOW, outputs follow the selected inputs. Schmitt-trigger CMOS input, 5.5 V tolerant.
16	VCC	power_in	Positive supply voltage. Recommended operating range 1.65 V to 3.6 V (functional down to 1.2 V); absolute maximum 6.5 V. Decouple locally to GND.

Key specifications

Parameter	Value
Manufacturer	Nexperia
Package	SOIC-16
Category	Logic
Pins	16

Ordering variants

74LVC257ADD
74LVC257ADPW
74LVC257ADBQ

CAD (KiCad official)

Symbol: 74LVC257AD
Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
3D model: SOIC-16 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`74lvc257ad.step`	217 KB	You want the bare part, or you mark your own boards.
`74lvc257ad-etched.step`	2.0 MB	You want the part with `74LVC257AD` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 522 faces against 267 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: Nexperia datasheet (14 pp, sha256 3a23e9adf4d0e855, 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