SN74HC21DR from Texas Instruments, in a SOIC-14. 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	1A	input	Channel 1, Input A. CMOS logic input to gate 1 (VIH ≥ 3.15 V @ VCC = 4.5 V; VIL ≤ 1.35 V @ VCC = 4.5 V).
2	1B	input	Channel 1, Input B. CMOS logic input to gate 1.
3	NC	unconnected	Not internally connected. Leave floating or tie to any potential.
4	1C	input	Channel 1, Input C. CMOS logic input to gate 1.
5	1D	input	Channel 1, Input D. CMOS logic input to gate 1.
6	1Y	output	Channel 1, Output Y. 1Y = 1A · 1B · 1C · 1D. CMOS push-pull output; IOL/IOH up to ±5.2 mA at VCC = 6 V.
7	GND	power_in	Ground return, 0 V reference for VCC and all inputs/outputs.
8	2Y	output	Channel 2, Output Y. 2Y = 2A · 2B · 2C · 2D. CMOS push-pull output; IOL/IOH up to ±5.2 mA at VCC = 6 V.
9	2A	input	Channel 2, Input A. CMOS logic input to gate 2.
10	2B	input	Channel 2, Input B. CMOS logic input to gate 2.
11	NC	unconnected	Not internally connected. Leave floating or tie to any potential.
12	2C	input	Channel 2, Input C. CMOS logic input to gate 2.
13	2D	input	Channel 2, Input D. CMOS logic input to gate 2.
14	VCC	power_in	Positive supply, 2 V to 6 V (absolute maximum 7 V). Bypass with a 0.1 µF ceramic capacitor to GND close to the pin.

Key specifications

Parameter	Value
Manufacturer	Texas Instruments
Package	SOIC-14
Category	Logic
Pins	14

Ordering variants

Same part, different packaging or reel option.

SN74HC21DRD
SN74HC21DR
SN74HC21DRN
SN74HC21DRNS
SN74HC21DRPW
SN74HC21DRJ
SN74HC21DRFK

CAD (KiCad official)

Symbol: SN74HC21DR
Footprint: Package_SO:SOIC-14_3.9x8.7mm_P1.27mm
3D model: SOIC-14 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`sn74hc21dr.step`	195 KB	You want the bare part, or you mark your own boards.
`sn74hc21dr-etched.step`	2.2 MB	You want the part with `SN74HC21DR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 558 faces against 237 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 (34 pp, sha256 d9553773c8d57248, 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