CH343G

CH343G is the SOP-16 variant of the WCH CH343, a USB bus converter chip that turns a USB port into a high-speed asynchronous serial (UART) interface with hardware full-duplex transfer from 50 bps to 6 Mbps, automatic identification and dynamic adaptation at baud rates of 115200 bps and below, and the full MODEM signal set (RTS, DTR, DCD, RI, DSR, CTS) plus TNOW for RS485 half-duplex switching (WCH CH343 datasheet, version 1E). The serial I/O rail is independent of the USB side and accepts 5 V, 3.3 V, 2.5 V or 1.8 V, the 12 MHz clock and power-on reset are integrated so no external crystal is needed, and each chip carries a unique USB serial number. Selection advice: of the three CH343 packages the SOP-16 G variant exposes every pin; the ESSOP-10 CH343K drops several MODEM lines and the VBUS pin, and the QFN16 CH343P is the only variant with an integrated EEPROM for configuring USB VID/PID and string descriptors - pick the package by the signals and configuration your design actually uses, because the pinouts are not interchangeable.