Two-wire remote I/O expansion chip CH423


The CH423 is a universal remote I/O expansion chip with a two-wire serial interface. CH423 provides 8 bidirectional input and output pins and 16 general-purpose output pins to support input level change interrupt. CH423 built-in current drive circuit can statically drive 24 LED tubes or dynamically drive 128 LEDs (equivalent to 16 digital) Tube); CH423 exchanges data with a single-chip microcomputer through a 2-wire serial interface.


  • 8 general-purpose input and output pins GPIO and 16 general-purpose output pin GPOs are remotely extended through a two-wire serial interface.
  • Built-in current drive stage, continuous drive current is not less than 15mA, OC pin output 1/16 pulse sink current is not less than 120mA.
  • The static display drive mode supports 24 LEDs or 3 LEDs.
  • The time-sharing dynamic scanning display drive mode supports 128 LEDs or 16-bit common cathode digital tubes, and supports brightness control.
  • The bidirectional I/O pin has an interrupt function when the input level changes in the input mode, and the interrupt output is active low.
  • The 16 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 DIP28S and SOP28 lead-free packages, compatible with RoHS.


relation files

file name file content
CH432DS1.PDF CH432 datasheet. Dual-UART expander. Compatible with 16C550. 8-bit parallel port or SPI to UART. Each UART receive/transmit data independently. Up to 4Mbps baud rate. Can be used for MCU dual-UART expansion. CH432 supports full-duplex/half-duplex/infrared modes.
CH452DS1.PDF CH452 datasheet. CH452 can be used for 64 LEDs or 8×8 segment digital tube drive and 64-key keyboard scanning control, simplifying the workload of MCU.
CH422DS1.PDF CH422 datasheet. Remote I/O expander chip of two-wire serial interface, used for display of 4 digital tubes and I/O expansion application. The input is a two-wire interface compatible with I2C, and the output is an 8-bit bidirectional I/O port and 4-bit large-current output port.
CH456DS1.PDF CH456 datasheet. CH456 is used for 16 digital tubes display drive and 64-key keyboard scanning. CH456 supports 2-wire serial interface, and is compatible with IIC, simplifying the workload of MCU.
CH446DS1.PDF CH446 datasheet. 8x16 matrix analog switch chip, contains 128 analog switches, used for arbitrary routing of 8x16 signal channels. CH446 supports 4V to 12V single supply voltage, and supports +5V and -7V dual power supply voltage. The ON resistance is not greater than 65Ω.
CH453DS1.PDF CH453 datasheet. CH453 can be used for 128 LEDs or 16×8 segment digital tube drive and 64-key keyboard scanning control.
CH463DS1.PDF CH463 datasheet, LCD display driver chip, 16 × 8 or 12 × 4 and other LCD display driver and 35-key keyboard scanning control, support for LCD backlight 64-level adjustment, 2-wire interface, compatible with I2C.