A single-chip USB 2.0 full-speed to UART bridge in QFN-28, the modern successor to the CP2102 and a common alternative to the FT232 and CH340. Everything needed sits on-chip: the USB transceiver, a 3.3 V regulator, the clock, and a one-time-programmable ROM holding the USB descriptors, so the whole design is the chip plus a couple of capacitors. It presents a virtual COM port to the host and transfers data at up to 3 Mbps, with the usual modem-control lines (RTS/CTS/DSR/DTR/DCD/RI) and several configurable GPIOs. Runs from the USB 5 V (self-powered) or 3.3 V.

Pinout

Pin	Name	Type	Function
1	DCD	input	Data Carrier Detect modem-control input (active low).
2	RI/CLK	bidirectional	Ring Indicator modem-control input (active low) or optional clock output (CLK). Function is selected by device configuration.
3	GND	power_in	Ground reference.
4	D+	bidirectional	USB 2.0 full-speed data positive line.
5	D-	bidirectional	USB 2.0 full-speed data negative line.
6	VDD	power_in	3.3 V core supply. Serves as the 3.3 V output of the internal 5 V-to-3.3 V regulator when VREGIN is powered, or as a direct 3.0-3.6 V supply input when the regulator is bypassed. Requires a 4.7 µF and 0.1 µF bypass capacitor close to the pin.
7	VREGIN	power_in	5 V voltage regulator input (3.6-5.25 V). Powers the internal regulator that produces 3.3 V on VDD. Tie to VBUS for bus-powered designs.
8	VBUS	input	VBUS sense digital input. Connect to the 5 V USB VBUS rail; a high level on this pin indicates that a USB host is attached.
9	RSTb	input	Active-low reset input. Recommend a 1 kΩ pull-up to VDD (or VIO on parts that have it). Driven low internally during power-on and power-failure reset events.
10	NC	unconnected	No connect. Leave this pin floating.
11	SUSPENDb	output	USB suspend indicator (active-low). Driven low when the device enters the USB suspend state.
12	SUSPEND	output	USB suspend indicator (active-high). Driven high when the device enters the USB suspend state.
13	CHREN	output	USB battery-charging enable output. Drives an external charging circuit at 100 mA.
14	CHR1	output	USB battery-charging current-select output. Enables highest charge current (1.5 A).
15	CHR0	output	USB battery-charging current-select output. Enables higher charge current (500 mA).
16	GPIO.3/WAKEUP	bidirectional	General-purpose I/O. Alternate function: remote USB wakeup interrupt input (WAKEUP).
17	GPIO.2/RS485	bidirectional	General-purpose I/O. Alternate function: RS485 transceiver direction-control output.
18	GPIO.1/RXT	bidirectional	General-purpose I/O. Alternate function: Receive LED toggle output (RXT).
19	GPIO.0/TXT	bidirectional	General-purpose I/O. Alternate function: Transmit LED toggle output (TXT).
20	GPIO.6	bidirectional	General-purpose digital I/O.
21	GPIO.5	bidirectional	General-purpose digital I/O.
22	GPIO.4	bidirectional	General-purpose digital I/O.
23	CTS	input	Clear-To-Send hardware-handshaking input (active low).
24	RTS	output	Ready-To-Send hardware-handshaking output (active low).
25	RXD	input	UART asynchronous data input (Receive). Supports baud rates from 300 baud to 3 Mbaud.
26	TXD	output	UART asynchronous data output (Transmit). Supports baud rates from 300 baud to 3 Mbaud.
27	DSR	input	Data Set Ready modem-control input (active low).
28	DTR	output	Data Terminal Ready modem-control output (active low).
EP	GND	power_in	Center exposed thermal pad. Must be connected to the board ground plane for electrical ground and heat dissipation.

Key specifications

Parameter	Value
Type	USB 2.0-to-UART bridge
USB	full-speed 12 Mbps (virtual COM port)
Max UART rate	3 Mbps
Integrated	USB PHY + regulator + clock + config ROM
Modem control	RTS/CTS/DSR/DTR/DCD/RI
GPIO	up to 7 configurable
Supply voltage	USB 5 V or 3.3 V
Package	QFN-28 (5x5 mm, EP)

Ordering variants

Same part, different packaging or reel option.

CP2102N-A01-GQFN28 (QFN-28)
CP2102N-A02-GQFN28R (QFN-28, tape & reel)

CAD (KiCad official)

Symbol: Interface_USB:CP2102N-Axx-xQFN28
Footprint: Package_DFN_QFN:QFN-28-1EP_5x5mm_P0.5mm_EP3.35x3.35mm
3D model: QFN-28 (KiCad packages3D)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Silicon Labs datasheet (48 pp, sha256 32fbab0ba17f394a, retrieved 2026-08-17, tier: manufacturer)
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