The ADP5589 is an I/O port expander and keypad matrix decoder designed for QWERTY type phones that require a large keypad matrix and expanded I/O lines. I/O expander ICs are used in mobile platforms ...

Many systems that require a user to manually enter data feature a keyboard similar to that in Figure 1. Although early keypads comprised arrays of individually wired switches, a typical modern keypad ...

Using eight digital inputs, this circuit simplifies decoding of the common membrane 4x4 keypad matrix and eliminates the traditional requirement of scanning rows or columns. Any X-Y switch matrix, ...