UMW3157 from UMW, in a SC-70-6. 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	B1	bidirectional	Analog/digital switch port B1. Connected to common port A when Select = H. Signal range 0 V to VCC; on-resistance typ. 5 Ω at VCC=4.5 V.
2	GND	power_in	Ground reference (0 V) for the device.
3	B0	bidirectional	Analog/digital switch port B0. Connected to common port A when Select = L. Signal range 0 V to VCC; on-resistance typ. 5 Ω at VCC=4.5 V.
4	A	bidirectional	Common analog/digital switch port A. Routed to B0 (Select=L) or B1 (Select=H). Bidirectional, signal range 0 V to VCC.
5	VCC	power_in	Positive supply voltage. Operating range 1.65 V to 5.5 V; absolute max 7.0 V. Bypass close to the pin.
6	Select	input	Digital select input controlling which B port is connected to A: L → B0-A, H → B1-A. Overvoltage-tolerant up to 7 V (may exceed VCC). Must be driven high or low; must not float.

Key specifications

Parameter	Value
Manufacturer	UMW
Package	SC-70-6
Category	Interface
Pins	6

Ordering variants

Same part, different packaging or reel option.

UMW3157DCKR

CAD (KiCad official)

Symbol: UMW3157
Footprint: Package_TO_SOT_SMD:SOT-363_SC-70-6
3D model: SC-70-6 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`umw3157.step`	99 KB	You want the bare part, or you mark your own boards.
`umw3157-etched.step`	1.4 MB	You want the part with `UMW3157` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 360 faces against 117 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: UMW datasheet (9 pp, sha256 bd8ed4cd0a78b39a, retrieved 2026-08-17, tier: lcsc)
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