SN74HC251PWR from Texas Instruments, in a TSSOP-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	D3	input	Data input 3. One of eight multiplexer data inputs; routed to outputs Y/W when select code CBA=011 and OE is low.
2	D2	input	Data input 2. One of eight multiplexer data inputs; selected when CBA=010.
3	D1	input	Data input 1. One of eight multiplexer data inputs; selected when CBA=001.
4	D0	input	Data input 0. One of eight multiplexer data inputs; selected when CBA=000.
5	Y	tri_state	True (non-inverted) 3-state data output. Drives the selected Dn value; high-impedance when OE is high. Rated ±6 mA at Vcc=5 V.
6	W	tri_state	Inverted (complementary) 3-state data output. Drives the logical inverse of the selected Dn value; high-impedance when OE is high. Rated ±6 mA at Vcc=5 V.
7	OE	input	Active-low output enable. When low, Y and W are driven by the selected Dn input; when high, both outputs are placed in high-impedance (3-state).
8	GND	power_in	Ground reference (0 V).
9	C	input	Select input C (MSB of the 3-bit binary channel select). Together with B and A chooses which Dn drives the outputs.
10	B	input	Select input B (middle bit of the 3-bit binary channel select).
11	A	input	Select input A (LSB of the 3-bit binary channel select).
12	D7	input	Data input 7. Selected when CBA=111.
13	D6	input	Data input 6. Selected when CBA=110.
14	D5	input	Data input 5. Selected when CBA=101.
15	D4	input	Data input 4. Selected when CBA=100.
16	VCC	power_in	Positive supply voltage. Recommended operating range 2 V to 6 V; absolute maximum 7 V.

Key specifications

Parameter	Value
Manufacturer	Texas Instruments
Package	TSSOP-16
Category	Logic
Pins	16

Ordering variants

Same part, different packaging or reel option.

SN74HC251PWR
SN74HC251PWRD
SN74HC251PWRDB
SN74HC251PWRN
SN74HC251PWRNS
SN74HC251PWRJ
SN74HC251PWRFK

CAD (KiCad official)

Symbol: SN74HC251PWR
Footprint: Package_SO:TSSOP-16_4.4x5mm_P0.65mm
3D model: TSSOP-16 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`sn74hc251pwr.step`	205 KB	You want the bare part, or you mark your own boards.
`sn74hc251pwr-etched.step`	2.6 MB	You want the part with `SN74HC251PWR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 652 faces against 255 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: Texas Instruments datasheet (31 pp, sha256 407441728ca2e20f, 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