The keypad control properties of cell phone chipsets are often stretched to their limits when an operating system or application needs to detect multiple keypresses (e.g. Ctrl-Alt-Del and gaming controls). This application note describes the MAX7359’s use as an ideal add-on key-switch controller for implementing multifunctional and gaming keys on a PDA/smartphone QWERTY keypad. The MAX7359 can be connected to the cell phone chipset through an IC interface, and simple program coding can be used to select a set of desired features.