USB to Octal Serial ports Chip CH348


CH348 is a high-speed USB bus converter chip, which converts USB to octal serial ports UART0/1/2/3/4/5/6/7, and used to expand serial ports for computer or upgrade directly from normal serial device or MCU to USB bus.


  • 480Mbps high-speed USB device interface, peripheral components only need crystal oscillator and capacitors.
  • Built-in firmware, emulate standard UART interface, used to upgrade the original serial peripheral or expand additional UART via USB.
  • Original serial applications are totally compatible without any modification in Windows operating systems.
  • Hardware full duplex UART interface, integrated independent transmit-receive buffer, supports communication baud rate varies from 1200bps to 6Mbps.
  • UART supports 8 data bits, supports odd, even, and none parity, supports 1 or 2 stop bits.
  • Integrated the 2048-byte RX FIFO and 1024-byte TX FIFO for each UART.
  • Supports common MODEM signals RTS, DTR, DCD, RI, DSR and CTS.
  • Supports CTS and RTS hardware automatic flow control.
  • Supports half-duplex, provides sending status TNOW, used for controlling RS485 to transmit-receive switch.
  • Supports up to 48-channel GPIO input and output function.
  • Supports RS232/RS485/RS422 interface, through external voltage conversion chip.
  • UART I/O of CH348L power supply independently, supports 3.3V, 2.5V, 1.8V power supply voltages.
  • Built-in EEPROM used to configure the chip of VID, PID, maximum current value, vendor and product information string, etc.
  • Supports only 3.3V power supply.
  • RoHS compliant LQFP48 and LQFP100 lead-free package.


Note: The USB transceiver of CH348 is designed according to the built-in design of USB2.0, and it is recommended that no external resistor is in series with UD+ and UD- pins.

relation files

file name file content
USBMSER.exe CH9344/CH348 USB to multi serial ports one-key installation driver for Windows, supports Windows 11/10/8.1/8/7/VISTA/XP/2000, Server 2022/2019/2016/2012/2008/2003 -32/64-bit. Microsoft WHQL/HCK Certified. Used to distribute to user with the product.
CH347DS1.PDF CH347 datasheet, 480Mbps high-speed USB to UART, I2C, SPI and JTAG, supports drivers on Windows/ Linux/ Android /macOS, used to high-speed USB to UART, USB to SPI, USB to IIC, USB to JTAG, CPU debugger,FPGA downloader,programming device etc.
CH340DS1.PDF CH340 datasheet, USB bus converter chip which converts USB to serial port, printer port, IrDA SIR etc. Integrated clock, supports various operating systems, chip information can be customized, this datasheet is about USB to serial port and USB to Infrared Adapter SIR.