CH340C 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 reference. Connect directly to the USB bus ground.
2	TXD	output	Serial data output (UART TX). Idles high on CH340C.
3	RXD	input	Serial data input (UART RX) with internal software-controllable pull-up and pull-down.
4	V3	power_in	Internal 3.3 V regulator node. In 5 V operation, connect a 0.1 uF decoupling capacitor to GND. In 3.3 V operation, tie V3 to VCC and to the external 3.3 V supply.
5	UD+	bidirectional	USB D+ data line. Connect directly to the USB bus D+; do not add a series resistor (internal USB pull-up and transceiver are integrated).
6	UD-	bidirectional	USB D- data line. Connect directly to the USB bus D-; do not add a series resistor.
7	NC	unconnected	No connect on CH340C. Must be left floating.
8	OUT#/DTR#	output	MODEM general-purpose output signal (software defined, active low). On CH340C batches whose lot code starts with 4 and whose last three digits are greater than B40, adding a 4.7 kΩ pull-down converts this pin to a second DTR#.
9	CTS#	input	MODEM Clear-To-Send handshake input, active low (or high when auxiliary RS-232 mode is enabled).
10	DSR#	input	MODEM Data Set Ready handshake input, active low (or high in auxiliary RS-232 mode).
11	RI#	input	MODEM Ring Indicator input, active low (or high in auxiliary RS-232 mode).
12	DCD#	input	MODEM Data Carrier Detect input, active low (or high in auxiliary RS-232 mode).
13	DTR#	output	MODEM Data Terminal Ready output, active low (or high in auxiliary RS-232 mode). Used for MCU DTR#-default-high one-key download flows.
14	RTS#	output	MODEM Request To Send output, active low (or high in auxiliary RS-232 mode).
15	R232	input	Auxiliary RS-232 enable input, active high, with internal pull-down. When high, an inverter is inserted on RXD and the MODEM signal polarities invert. Sampled only once at power-on reset.
16	VCC	power_in	Positive supply input. Requires a 0.1 uF decoupling capacitor to GND. Accepts 5 V (4.0-5.3 V) or 3.3 V (3.1-3.6 V, with V3 tied to VCC).

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.

CH340C
CH340G
CH340B
CH340N
CH340K
CH340E
CH340X
CH340T
CH340R

CAD (KiCad official)

Symbol: CH340C
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
`ch340c.step`	217 KB	You want the bare part, or you mark your own boards.
`ch340c-etched.step`	2.0 MB	You want the part with `CH340C` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 488 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 ea6cde8472044256, 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