MAX7359

2-Wire Interfaced Low-EMI Key Switch Controller/GPO

Low-Voltage, Low-EMI, and Low-Supply Current Key-Switch Controller Monitors Up to 64 Keys Without External Components


Please check latest availability status for a specific part variant.

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.

The key controller debounces and maintains a FIFO of key-press and release events (including autorepeat, if enabled). An interrupt (active-low INT) output can be configured to alert key presses either as they occur, or at maximum rate.

Any of the column drivers (COL2/PORT2–COL7/PORT7) or the active-low INT, if not used, can function as a general-purpose output (GPO).

The MAX7359 is offered in small, 24-pin TQFN (3.5mm x 3.5mm) and 25-bump WLP (2.31mm x 2.31mm) packages for cell phones, pocket PCs, and other portable consumer electronic applications. The MAX7359 operates over the -40°C to +85°C temperature range.
MAX7359: Typical Application Circuit MAX7359: Typical Application Circuit Enlarge+

Key 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) , or 25-Pin WLP Package (2.31mm x 2.31mm)

Applications/Uses

  • Cell Phones
  • Handheld Games
  • PDAs
  • Portable Consumer Electronics
Part NumberInterfaceKeysISUPPLY
(µA)
ISHUTDN
(µA)
Interr. OutKey Scan I2C Slave IDsGPIOVSUPPLY
(V)
Package/PinsBudgetary
Price
maxtyptypSee Notes
MAX7359 Serial 2-Wire 400kbit64251Yes46 GPO1.62 to 3.6
TQFN/24
WLP/25
$3.78 @1k
See All Keyswitch Controllers (4)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


MAX7359EVKIT: Evaluation Kit for the MAX7359

CAD Symbols and Footprints

  • MAX7359BETG+
  • MAX7359BETG+T
  • MAX7359ETG+
  • MAX7359ETG+G47
  • MAX7359ETG+T
  • MAX7359ETG+TG47
  • MAX7359EWA+
  • MAX7359EWA+T
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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