General Description
The MAX7359 I2C interfaced peripheral provides microprocessors with management of up to 64 key switches. Key codes are generated for each press and release of a key for easier implementation of multiple key entries. Key inputs are monitored statically, not dynamically, to ensure low-EMI operation. The switches can be metallic or resistive (carbon) with up to 5kΩ of resistance.
The MAX7359 features autosleep and autowake to further minimize the power consumption of the device. The autosleep feature puts the device in a low-power state (1µA typ) after a sleep timeout period. The autowake feature configures the MAX7359 to return to normal operating mode from sleep upon a key press.

Features
♦ Optional Key Release Detection on All Keys
♦ Monitor Up to 64 Keys
♦ 1.62V to 3.6V Operation
♦ Autosleep and Autowake to Minimize Current
   Consumption
♦ Under 1µA Sleep Current
♦ FIFO Queues Up to 16 Debounced Key Events
♦ Key Debounce Time User Configurable from 9ms
   to 40ms
♦ Low-EMI Design Uses Static Matrix Monitoring
♦ Hardware Interrupt at the FIFO Level or at the End
   of Definable Time Period
♦ Up to Seven Open-Drain Logic Outputs Available
   Capable of Driving LEDs
♦ 400kbps, 5.5V-Tolerant, 2-Wire Serial Interface
♦ Selectable 2-Wire, Serial-Bus Timeout
♦ Four I2C Address Choices
♦ Small, 24-Pin TQFN Package (3.5mm x 3.5mm)

Applications
   Cell Phones
   PDAs
   Handheld Games
   Portable Consumer Electronics