SN74HC139DR from Texas Instruments, 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	1G	input	Active-low enable (strobe) input for decoder 1. When high, all decoder-1 outputs (1Y0-1Y3) are forced high. When low, the selected 1Y output is driven low.
2	1A	input	Decoder 1 address select input A (LSB). Combined with 1B, selects which of the four 1Y outputs is driven low when the decoder is enabled.
3	1B	input	Decoder 1 address select input B (MSB). Combined with 1A, selects which of the four 1Y outputs is driven low when the decoder is enabled.
4	1Y0	output	Decoder 1 output 0 (active low). Driven low when 1G is low and 1A=0, 1B=0. Rated for +/-4 mA drive at Vcc = 4.5 V.
5	1Y1	output	Decoder 1 output 1 (active low). Driven low when 1G is low and 1A=1, 1B=0. Rated for +/-4 mA drive at Vcc = 4.5 V.
6	1Y2	output	Decoder 1 output 2 (active low). Driven low when 1G is low and 1A=0, 1B=1. Rated for +/-4 mA drive at Vcc = 4.5 V.
7	1Y3	output	Decoder 1 output 3 (active low). Driven low when 1G is low and 1A=1, 1B=1. Rated for +/-4 mA drive at Vcc = 4.5 V.
8	GND	power_in	Ground reference (0 V). Connect to system ground.
9	2Y3	output	Decoder 2 output 3 (active low). Driven low when 2G is low and 2A=1, 2B=1. Rated for +/-4 mA drive at Vcc = 4.5 V.
10	2Y2	output	Decoder 2 output 2 (active low). Driven low when 2G is low and 2A=0, 2B=1. Rated for +/-4 mA drive at Vcc = 4.5 V.
11	2Y1	output	Decoder 2 output 1 (active low). Driven low when 2G is low and 2A=1, 2B=0. Rated for +/-4 mA drive at Vcc = 4.5 V.
12	2Y0	output	Decoder 2 output 0 (active low). Driven low when 2G is low and 2A=0, 2B=0. Rated for +/-4 mA drive at Vcc = 4.5 V.
13	2B	input	Decoder 2 address select input B (MSB). Combined with 2A, selects which of the four 2Y outputs is driven low when the decoder is enabled.
14	2A	input	Decoder 2 address select input A (LSB). Combined with 2B, selects which of the four 2Y outputs is driven low when the decoder is enabled.
15	2G	input	Active-low enable (strobe) input for decoder 2. When high, all decoder-2 outputs (2Y0-2Y3) are forced high. When low, the selected 2Y output is driven low.
16	VCC	power_in	Positive supply voltage. Operating range 2 V to 6 V (absolute max 7 V). Decouple with a 100 nF ceramic capacitor to GND close to the pin.

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

SN74HC139DRD
SN74HC139DR
SN74HC139DRDB
SN74HC139DRDBR
SN74HC139DRN
SN74HC139DRNS
SN74HC139DRNSR
SN74HC139DRPW
SN74HC139DRPWR
SN74HC139DRJ
SN74HC139DRFK
SN74HC139DRW

CAD (KiCad official)

Symbol: SN74HC139DR
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
`sn74hc139dr.step`	217 KB	You want the bare part, or you mark your own boards.
`sn74hc139dr-etched.step`	2.6 MB	You want the part with `SN74HC139DR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 654 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: Texas Instruments datasheet (30 pp, sha256 7bed90a2f9c2fe80, 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