CH443K from WCH Jiangsu Qin Heng, in a SC-70-6(SOT-363). 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	CH1	passive	Analog switch throw #2 (S2B). Connected to COM when SEL = high. Recommended analog signal range 0 to 2.8 V (VANA), absolute limit -0.3 to VCC+0.3 V. Ron ≈ 5 Ω typ.
2	GND	power_in	Common ground, digital signal reference.
3	CH0	passive	Analog switch throw #1 (S1B). Connected to COM when SEL = low. Recommended analog signal range 0 to 2.8 V (VANA), absolute limit -0.3 to VCC+0.3 V. Ron ≈ 5 Ω typ.
4	COM	passive	Common pole (DB) of the SPDT analog switch. Routed to CH0 when SEL=0 and to CH1 when SEL=1. Bidirectional analog path.
5	VCC	power_in	Positive supply. Rated 5 V (operating 4.0-5.5 V), abs max 6.5 V. Static ICC ≈ 0.1 µA typ with digital pins tied to rails.
6	SEL	input	Digital channel-select input. SEL=low selects CH0→COM; SEL=high selects CH1→COM. VIL max 1.0 V, VIH min 2.0 V (referenced to VCC).

Key specifications

Parameter	Value
Manufacturer	WCH Jiangsu Qin Heng
Package	SC-70-6(SOT-363)
Category	Interface
Pins	6

Ordering variants

Same part, different packaging or reel option.

CH443K

CAD (KiCad official)

Symbol: CH443K
Footprint: Package_TO_SOT_SMD:SOT-363_SC-70-6
3D model: SC-70-6(SOT-363) (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ch443k.step`	99 KB	You want the bare part, or you mark your own boards.
`ch443k-etched.step`	1.2 MB	You want the part with `CH443K` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 323 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: WCH Jiangsu Qin Heng datasheet (16 pp, sha256 608400255c2b0865, 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