The WCH CH340 datasheet provides specifications, pin descriptions, electrical parameters, and application examples for the USB‑to‑serial converter chip.
The CH340 is a USB bus converter chip that can translate USB to standard serial, IrDA infrared, or printer interfaces. It supports full‑speed USB 2.0, a wide range of baud rates, and common modem control signals, making it suitable for upgrading legacy serial devices to USB.
The datasheet details the SSOP‑20 package, pin functions, absolute maximum ratings, electrical parameters, and example application circuits for USB‑to‑RS232, USB‑to‑TTL, and USB‑to‑infrared adapters. Design notes cover decoupling, crystal placement, and PCB layout recommendations.
| Operating temperature | -40 °C to 85 °C |
|---|---|
| Storage temperature | -55 °C to 125 °C |
| Input voltage low (VIL) | -0.5 V |
| Input voltage high (VIH) | 2.0 V |
| Typical current consumption | 12 mA (max 30 mA) at 5 V |
| Baud‑rate range | 50 bps to 2 Mbps |
The CH340 can operate from either a 5 V or a 3.3 V source voltage.
It provides RTS, DTR, DCD, RI, DSR, and CTS signals.
The chip is supplied in an SSOP‑20 surface‑mount package.
The USB bus can supply up to 500 mA to the CH340.