CH340N from WCH Jiangsu Qin Heng, in a SOP-8. 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	UD+	bidirectional	USB D+ data line. Connect directly to the USB bus D+; do not add a series resistor. Internal pull-up and full USB 2.0 full-speed transceiver are integrated.
2	UD-	bidirectional	USB D- data line. Connect directly to the USB bus D-; do not add a series resistor.
3	GND	power_in	Common ground. Connect directly to the USB bus ground.
4	RTS#	output	MODEM Request-To-Send output, active low (software-controllable polarity). Only MODEM handshake line brought out on the SOP-8 CH340N.
5	VCC	power_in	Positive supply input. Supports 5V (4.0-5.3V) or 3.3V (3.1-3.6V) operation. Requires a 0.1uF decoupling capacitor. In 3.3V mode, tie VCC to V3 (pin 8).
6	TXD	output	UART serial data output. Idle-high in normal (non-IrDA) mode. Baud rates 50 bps to 2 Mbps; transmit baud error <1.8% on CH340N (internal oscillator).
7	RXD	input	UART serial data input. Has software-controllable internal pull-up and pull-down resistors. Should idle high.
8	V3	power_out	Internal 3.3V regulator node. In 5V operation, connect a 0.1uF decoupling capacitor to GND. In 3.3V operation, tie directly to VCC (pin 5) and feed 3.3V externally.

Key specifications

Parameter	Value
Manufacturer	WCH Jiangsu Qin Heng
Package	SOP-8
Category	Interface
Pins	8

Ordering variants

Same part, different packaging or reel option.

CH340N
CH340G
CH340C
CH340B
CH340K
CH340E
CH340X
CH340T
CH340R

CAD (KiCad official)

Symbol: CH340N
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOP-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ch340n.step`	122 KB	You want the bare part, or you mark your own boards.
`ch340n-etched.step`	1.5 MB	You want the part with `CH340N` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 368 faces against 147 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 (10 pp, sha256 6a6922d3c4de2d4f, 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