Keypad controllers boast low current drain

Analog Devices Inc. introduces the ADP5585 and ADP5589 GPIO (general-purpose input/output) port expander and keypad matrix controllers for devices that require expanded I/O lines or mechanical keypads up to QWERTY size. The GPIO/keypad controllers feature low active current drain and integrated programmable logic/PWM (pulse-width modulator) in small package. These GPIO/keypad controllers save battery life in portable devices by consuming less than 30?A (typical) when keys are pressed and less than 1uA (typical) when the keys are idle.

The ADP5585 and ADP5589 simplify interface connectors by saving up to 10 I/O lines (ADP5585) and 19 I/O lines (ADP5589) to the main processor. Both keypad controllers support multiple, simultaneous key press detection and communicate presses and releases in a chronological order via a 16byte FIFO. In addition to the built-in programmable logic devices, two programmable reset generators allow designers to program keys, GPIOs, and/or logic changes to generate a reset signal to restart a locked up processor. Both devices are available in small LFCSP (ADP5585: 3 x 3mm; ADP5589: 3.5 x 3.5mm) and WLCSP packages (ADP5585: 1.59 x 1.59mm; ADP5589: 1.99 x 1.99mm).

The ADP5585 and ADP5589 are designed for devices with front-panel keypads that need to expand the number of GPIO ports without increasing pin count. Both devices free up the main processor from having to monitor the keypad, thereby reducing power consumption and increasing processor bandwidth for other functions. The controllers handle all key scanning and decoding functions and use an interrupt line to flag the main processor when new key events have occurred. Both the ADP5585 and ADP5589 are equipped with FIFO registers that store up to 16 events which are then read back by the processor through an I²C -compatible interface. Evaluation boards and Linux software drivers are available to provide the necessary tools to implement designs quickly and efficiently.

The ADP5585 is available now in 160-Lead LFCSP and 16-bump WLCSP packaging, and priced at $0.75. The ADP5589 is available now, in 24-lead LFCSP and 25-bump WLCSP packaging, and priced at $1.20. Their respective evaluation boards (ADP5585CP-EVALZ and ADP5589CP-EVALZ) are also available now, priced at $160.