SN74HC166DR 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	SER	input	Serial data input. Shifted into the register on the rising edge of CLK when SH/LD is high.
2	A	input	Parallel input A. Loaded into shift-register stage A on the next clock rising edge when SH/LD is low.
3	B	input	Parallel input B. Loaded into shift-register stage B on the next clock rising edge when SH/LD is low.
4	C	input	Parallel input C. Loaded into shift-register stage C on the next clock rising edge when SH/LD is low.
5	D	input	Parallel input D. Loaded into shift-register stage D on the next clock rising edge when SH/LD is low.
6	CLK INH	input	Clock inhibit input. When held high, inhibits clocking; should transition high only while CLK is high to avoid glitches.
7	CLK	input	Clock input, positive-edge triggered. Shifts or loads the register on the rising edge depending on SH/LD.
8	GND	power_in	Ground reference (0 V).
9	CLR	input	Active-low asynchronous clear. Overrides all other inputs, including CLK, and resets all flip-flops to zero.
10	E	input	Parallel input E. Loaded into shift-register stage E on the next clock rising edge when SH/LD is low.
11	F	input	Parallel input F. Loaded into shift-register stage F on the next clock rising edge when SH/LD is low.
12	G	input	Parallel input G. Loaded into shift-register stage G on the next clock rising edge when SH/LD is low.
13	QH	output	Serial data output from the last (H) shift-register stage. Drives ±4 mA at VCC = 5 V.
14	H	input	Parallel input H. Loaded into shift-register stage H on the next clock rising edge when SH/LD is low.
15	SH/LD	input	Shift/load mode select. High enables serial shifting from SER; low enables synchronous parallel load from A-H on the next CLK rising edge.
16	VCC	power_in	Positive supply rail, 2 V to 6 V (5 V nominal).

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

SN74HC166DRD
SN74HC166DR
SN74HC166DRDB
SN74HC166DRDBR
SN74HC166DRN
SN74HC166DRNS
SN74HC166DRNSR
SN74HC166DRPW
SN74HC166DRPWR
SN74HC166DRJ
SN74HC166DRFK

CAD (KiCad official)

Symbol: SN74HC166DR
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
`sn74hc166dr.step`	217 KB	You want the bare part, or you mark your own boards.
`sn74hc166dr-etched.step`	2.6 MB	You want the part with `SN74HC166DR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 647 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 (41 pp, sha256 6e3f10dd0226bea6, 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