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USB to serial port chip CH340

USB to serial port chip CH340


1 . Overview


CH340 is a USB bus adapter chip, which can realize USB to serial port or USB to print port.


In serial port mode, CH340 provides common MODEM contact signals, which are used to expand asynchronous serial ports for computers, or use common Serial device upgrade directly to USB bus

2. Features


Full-speed USB device interface, compatible with USB V2.0.


Emulates standard serial ports for upgrading original serial peripherals, or adding additional serial ports via USB.


The serial port applications under the Windows operating system on the computer side are fully compatible and do not need to be modified.


Hardware full-duplex serial port, built-in transceiver buffer, support communication baud rate 50bps ~ 2Mbps.


Support common MODEM contact signals RTS, DTR, DCD, RI, DSR, CTS.


By adding a level conversion device, it provides interfaces such as RS232, RS485, and RS422.


CH340R chip supports IrDA standard SIR infrared communication, supports baud rate from 2400bps to 115200bps.


The software is compatible with CH341, and the driver of CH341 can be used directly.


5V supply voltage and 3.3V supply voltage and even 3V supply voltage are supported.


CH340C and CH340B have built-in clock without external crystal oscillator, CH340B also has built-in EEPROM for configuring serial number and so on.


Available in SOP-16 and SSOP-20 lead-free packages, RoHS compliant.


CH340 chip supports 5V power supply voltage or 3.3V power supply voltage. When using 5V working voltage, the VCC pin of CH340 chip

Input an external 5V power supply, and the V3 pin should be connected to a power supply decoupling capacitor with a capacity of 0.1uF. 


When using 3.3V operating voltage,The V3 pin of the CH340 chip should be connected to the VCC pin, input an external 3.3V power supply, and connect to the CH340 chip, The operating voltage of other circuits cannot exceed 3.3V


CH340 can be used to upgrade the original serial peripheral devices, or add additional serial ports to the computer through the USB bus. through the applied level The conversion device can further provide RS232, RS485, RS422 and other interfaces.


Premier Cable  Co. Ltd, Website :,  is a factory based in Dong Guan to make : 


USB bus adapter 


Raspberry Pi Cable


RS485 RS232 cables


USB to TTL FTDI cables 

USB to serial port chip CH340



Tel : 0086-0139-2949-7934


Skype : james198585 



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