The DataSheet of CH450 (the first)
LED drive and keyboard control chip CH450
CH450 is numeric LEDs display drive and keyboard scan control chip. CH450 sets clock surging
circuit internal, drives six bits numeric LEDs or forty-eight LEDs automatically. And it carries out
forty-eight keys keyboard scan. CH450 exchanges data with MCU via two wires serial interface and supplies
power-up reset signal to MCU.
● Set display current drive layer internal, the segment current is no less than 15mA, the word current is no
less than 80mA.
● Dynamically display scan control, directly drive six bits numeric LEDs or forty eight LEDs.
● Set forty eight keys keyboard controller internal, basic on 8×6 matrix keyboard scan.
● Set pull-down resistor internal on the key pressed station, and set eliminate dithering circuit internal.
● Supplies keyboard interrupt active with low-level, supplies key-press release sign bit, to detect key is
pressed or released.
● High-speed two wires serial interface, the speed of clock varies from 0 to 4MHz,compatible with two
wires I2C bus, save pins.
● Set clock surge circuit internal, the outside supplies clock or surging equipments is no need, stand against
● Set clock surging circuit internal, don’t need outside to provide clock or connect surge device,
anti-jamming capability is more stronger.
● Set power-on reset internal, supplies reset output active with high-level to MCU.
● Supplies DIP20 and SOP20 package without lead, compatible with RoHS, the function and pins are
compatible with CH455 in some parts.