CH340 PDF Datasheet – USB to Serial Chip

What is CH340?

This is a USB-to-serial chip used for communication between a computer and a microcontroller or other embedded device. It is commonly used in electronics projects and is popular due to its low cost and ease of use.

Function: USB to Serial Chip

Package: SOP-20 Pin type



2 page
CH340 pdf datasheet


CH340 is a USB bus convert chip and it can realize USB convert to serial interface, USB convert to IrDA infrared or USB convert to printer interface. In serial interface mode, CH340 supplies common MODEM liaison signal, used to enlarge asynchronous serial interface of computer or upgrade the common serial device to USB bus directly. More detail about USB convert to printer interface please referring to the second manual CH340DS2. In infrared mode, add infrared transceiver to CH340 can compose USB infrared adapter, realize SIR infrared communication.


1. Full speed USB device interface, conforms to USB Specification Version 2.0, only needs crystal and
capacitance external.

2. Emulate standard serial interface, used to upgrade the former peripheral device, or add excess serial
interface through USB.

3. Totally compatible with serial application program in computer endpoint Windows operation system.

4. Hardware full duplex serial interface, set transceiver buffer, supports communication baud rate varies from 50bps to 2Mbps.

CH340 pinout


1. USB 2.0 full-speed device interface, compatible with USB 1.1

2. Supports data transfer rates up to 2 Mbps

3. Supports common serial communication protocols such as UART, SPI, and I2C

4. Widely available and supported by many development environments and programming languages

5. Can be used with a variety of microcontrollers and embedded devices


CH340 PDF Datasheet