Digital Tube Display Driver and I/O Expansion Chip CH422


The CH422 chip can be used for digital tube display drivers or I/O expansion. CH422 has built-in clock oscillation circuit, which can dynamically drive 4-digit digital tube or 32 LED light-emitting tubes. When CH422 is used for I/O expansion, it can provide 8 bidirectional input and output pins and 4 general-purpose output pins;CH422 exchanges data with a single-chip microcomputer through a 2-wire serial interface.


  • Dynamic display scan control, direct drive 4-digit digital tube or 32 LED tubes.
  • Built-in current drive stage, the segment current drive capability is not less than 15mA, and the output word current is not less than 100mA.
  • Built-in clock oscillating circuit, no need to provide external clock or external oscillating components, more anti-interference.
  • 8 general-purpose input and output pins GPIO and 4 general-purpose output pin GPOs are remotely extended through a two-wire serial interface.
  • Four general-purpose output pins can be selected for push-pull output or open-drain output.
  • Supports 3V ~ 5V power supply voltage, supports low-power sleep, can be awakened by input level changes.
  • High-speed 2-wire serial interface with clock speeds from 0 to 1MHz, compatible with two-wire I2C bus, saving pins.
  • Available in SOP16 lead-free package, compatible with RoHS.