Part: WCH CH340

Type: USB to Serial Converter

Description: USB V2.0 compatible device interface that emulates a standard UART, supporting baud rates from 50bps to 2Mbps, with variants offering built-in crystal and EEPROM for configuration.

Operating Conditions:

• Supply voltage: 2.8–5.3 V
• Operating temperature: -40 to +85 °C
• UART baud rate: 50bps to 2Mbps
• Input clock frequency: 11.98–12.02 MHz (for variants requiring external crystal)

Absolute Maximum Ratings:

• Max supply voltage: 6.0 V
• Max continuous current: null
• Max junction/storage temperature: 125 °C

Key Specs:

• Operating Supply Current (CH340G/C/E/T/R, Normal Operation): 7 mA (Typ), 20 mA (Max)
• Operating Supply Current (CH340B, Normal Operation): 6 mA (Typ), 15 mA (Max)
• Suspend Supply Current (VCC=5V): 0.1 mA (Typ), 0.2 mA (Max)
• Low-level Input Voltage (VIL): -0.5 V (Min), 0.7 V (Max)
• High-level Input Voltage (VIH): 2.0 V (Min), VCC+0.5 V (Max)
• Low-level Output Voltage (VOL, 4mA draw current): 0.5 V (Max)
• High-level Output Voltage (VOH, 3mA output current): VCC-0.5 V (Min)

Features:

• Full speed USB device interface, compatible with USB V2.0.
• Emulates standard UART interface, supports 50bps to 2Mbps baud rate.
• Supports common MODEM liaison signals (RTS, DTR, DCD, RI, DSR, CTS).
• Supports 5V, 3.3V, and 3V power supply.
• CH340C, CH340E, CH340B have built-in crystal, no external crystal required.
• CH340B integrates EEPROM for configuring serial number and other information.
• CH340R supports IrDA criterion SIR infrared communication.

Applications:

• USB to RS232 Converter
• USB to TTL Converter
• USB to Infrared Adapter
• USB to RS485 Converter

Package:

• SOP-16
• MSOP-10
• SSOP-20

• Full speed USB device interface, compatible with USB V2.0.
• Emulate standard UART interface, used to upgrade the serial peripherals, or expand UART interface via USB bus.
• Original serial applications are totally compatible, without any modification in Windows operation system.
• Hardware full duplex serial UART interface, built-in transmit-receive buffer, supports communication baud rate varies from 50bps to 2Mbps.
• Supports common MODEM liaison signal RTS, DTR, DCD, RI, DSR and CTS.
• Through external level conversion chip provide further RS232, RS485, RS422 interface, etc.
• CH340R supports IrDA criterion SIR infrared communication, supports baud rate varies from 2400bps to 115200bps.
• Software compatible with CH341, use driver of CH341 directly.
• Support 5V and 3.3V power supply even 3V.
• CH340C, CH340E and CH340B have built-in crystal, no external crystal, CH340B also integrates EEPROM used to configure the serial number, etc.
• SOP-16 and SSOP-20 and MSOP-10 lead-free RoHS compliant package.

CH340G/C/T/R Pinout

Package: SOP-16 (CH340G/C), SSOP-20 (CH340T/R)

Notes

• CH340G/C (SOP-16): Uses pins 1–16 as listed above.
• CH340T/R (SSOP-20): The SOP-16 pinout above maps to SSOP-20 pins 8, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 18, 19 respectively. Additional SSOP-20 pins are: Pin 1 (CK0 for CH340T / NC for CH340R), Pin 2 (ACT#), Pin 17 (TNOW for CH340T / IR# for CH340R), Pin 20 (NOS#).
• XI/XO pins (7, 8): CH340G/T/R require external 12 MHz crystal oscillator; CH340C has built-in oscillator and these pins must be suspended.
• R232 pin (15): When driven high, enables internal inverter on RXD pin for RS232 compatibility.
• CH340R specifics: TXD output is inverted (low when idle); IR# pin (pin 17 on SSOP-20) selects SIR infrared mode when low.
• MODEM signals (9–14): All active low by default; polarity controlled by software/driver.
• V3 pin (4): For 5V operation, connect 0.1μF capacitor to ground; for 3.3V operation, connect directly to VCC.