CH340G from WCH Jiangsu Qin Heng, in a SOP-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	GND	power_in	Common ground. Connect directly to the USB bus ground.
2	TXD	output	Serial data output. Idle-high in normal UART mode. Drives external MCU RXD or an RS232/RS485 level shifter.
3	RXD	input	Serial data input with controllable internal pull-up/pull-down. Should be high when idle. If R232 pin is high, an internal inverter is inserted (default low).
4	V3	power_in	Internal 3.3 V regulator node. At 5 V operation, connect a 0.1 uF decoupling capacitor to GND. At 3.3 V operation, tie V3 to VCC (both fed by external 3.3 V rail).
5	UD+	bidirectional	USB D+ data line. Connect directly to the USB bus D+; do NOT add a series resistor. Internal USB pull-up is built in.
6	UD-	bidirectional	USB D- data line. Connect directly to the USB bus D-; do NOT add a series resistor.
7	XI	input	Crystal oscillator input. Requires an external 12 MHz crystal between XI and XO with load capacitors (typ. 33 pF) to GND on each side.
8	XO	output	Crystal oscillator output. Pairs with XI for the 12 MHz crystal reference.
9	CTS#	input	MODEM handshake input: Clear To Send. Active low (or high if R232 auxiliary RS232 mode is enabled).
10	DSR#	input	MODEM handshake input: Data Set Ready. Active low (or high in auxiliary RS232 mode).
11	RI#	input	MODEM handshake input: Ring Indicator. Active low (or high in auxiliary RS232 mode).
12	DCD#	input	MODEM handshake input: Data Carrier Detect. Active low (or high in auxiliary RS232 mode).
13	DTR#	output	MODEM handshake output: Data Terminal Ready. Active low (or high in auxiliary RS232 mode). Doubles as a configuration input before USB enumeration (external 4.7 kΩ pull-down requests higher bus current in descriptor).
14	RTS#	output	MODEM handshake output: Request To Send. Active low (or high in auxiliary RS232 mode).
15	R232	input	Auxiliary RS232 mode enable. High enables auxiliary RS232 (inverts RXD input automatically and allows discrete-transistor RS232 conversion). Internal pull-down; sampled only once after power-on reset.
16	VCC	power_in	Positive supply input. Accepts 5 V (typ. 4.0-5.3 V) with V3 decoupled to GND via 0.1 uF, or 3.3 V (typ. 2.9-3.6 V) with V3 shorted to VCC. Requires a 0.1 uF decoupling capacitor.

Key specifications

Parameter	Value
Manufacturer	WCH Jiangsu Qin Heng
Package	SOP-16
Category	Interface
Pins	16

Ordering variants

Same part, different packaging or reel option.

CH340GG
CH340GC
CH340GB
CH340GN
CH340GK
CH340GE
CH340GX
CH340GT
CH340GR

CAD (KiCad official)

Symbol: CH340G
Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
3D model: SOP-16 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ch340g.step`	217 KB	You want the bare part, or you mark your own boards.
`ch340g-etched.step`	2.0 MB	You want the part with `CH340G` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 496 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: 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