CH552G 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	P3.2/TXD1_/INT0/VBUS1/AIN3	bidirectional	Port 3 bit 2 GPIO. Multiplexed with UART1 TXD1 mapping, external interrupt INT0, USB Type-C VBUS1 sense input, and ADC channel AIN3.
2	P1.4/T2_/CAP1_/SCS/TIN2/UCC1/AIN1	bidirectional	Port 1 bit 4 GPIO. Alt functions: Timer2 clock T2 (mapped), Timer2 capture CAP1, SPI0 chip-select SCS, Touch-Key TIN2, USB Type-C CC1 detect UCC1, ADC channel AIN1.
3	P1.5/MOSI/PWM1/TIN3/UCC2/AIN2	bidirectional	Port 1 bit 5 GPIO. Alt: SPI0 MOSI (master out / slave in), PWM1 output, Touch-Key TIN3, USB Type-C CC2 detect UCC2, ADC channel AIN2.
4	P1.6/MISO/RXD1/TIN4	bidirectional	Port 1 bit 6 GPIO. Alt: SPI0 MISO, UART1 RXD1 receive input, Touch-Key channel TIN4.
5	P1.7/SCK/TXD1/TIN5	bidirectional	Port 1 bit 7 GPIO. Alt: SPI0 SCK clock, UART1 TXD1 transmit output, Touch-Key channel TIN5.
6	RST/T2EX_/CAP2_	input	External reset input (active high). Also selectable as Timer2 reload/capture input T2EX and capture CAP2 (mapped variants). Has internal pull-down resistor; other GPIOs default to pull-up.
7	P3.1/PWM2_/TXD	bidirectional	Port 3 bit 1 GPIO. Alt: PWM2 output (mapped), UART0 TXD serial transmit.
8	P3.0/PWM1_/RXD	bidirectional	Port 3 bit 0 GPIO. Alt: PWM1 output (mapped), UART0 RXD serial receive.
9	P1.1/T2EX/CAP2/TIN1/VBUS2/AIN0	bidirectional	Port 1 bit 1 GPIO. Alt: Timer2 external reload T2EX, Timer2 capture CAP2, Touch-Key channel TIN1, USB Type-C VBUS2 sense, ADC channel AIN0.
10	P3.3/INT1	bidirectional	Port 3 bit 3 GPIO. Alt: external interrupt INT1 input.
11	P3.4/PWM2/RXD1_/T0	bidirectional	Port 3 bit 4 GPIO. Alt: PWM2 output, UART1 RXD1 (mapped alt), Timer0 external clock T0.
12	P3.6/UDP	bidirectional	Port 3 bit 6 GPIO, dual-function USB D+ line (UDP). USB transceiver is USB 2.0 full-speed compliant; when used as USB no series termination resistor is required. As GPIO, uses V33 as its I/O rail so high level is limited to V33 (not 5 V tolerant).
13	P3.7/UDM	bidirectional	Port 3 bit 7 GPIO, dual-function USB D- line (UDM). USB 2.0 full-speed compliant transceiver; no external series termination required when used as USB. GPIO logic level tied to V33 rail (not 5 V tolerant).
14	GND	power_in	Common ground (VSS).
15	VCC	power_in	Main supply input (VDD), 3.3 V or 5 V. Requires an external 0.1 µF decoupling capacitor.
16	V33	power_in	Internal USB 3.3 V LDO regulator output and USB I/O supply input. When VCC < 3.6 V, tie V33 to VCC externally. When VCC > 3.6 V (5 V operation), leave V33 as regulator output and connect an external 0.1 µF decoupling capacitor.

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

CH552G
CH552T
CH552P
CH552E

CAD (KiCad official)

Symbol: CH552G
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
`ch552g.step`	217 KB	You want the bare part, or you mark your own boards.
`ch552g-etched.step`	2.0 MB	You want the part with `CH552G` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 487 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 (53 pp, sha256 b3995c47a6c00a9f, retrieved 2026-08-17, tier: lcsc)
Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
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