TCA8418E I2C Controlled Keypad Scan IC With Integrated ESD Protection

 

TCA8418E

I2C Controlled

Keypad Scan IC

With Integrated ESD Protection

http://focus.ti.com/docs/prod/folders/print/tca8418e.html?HQS=hpa_tca8418e_191210&DCMP=mytinwsltr_12_18_2010&sp_rid_pod3=LTY0NjUzMzE2OAS2&sp_mid_pod3=495039

Features
  • Operating Power-Supply Voltage Range of 1.65 V to 3.6 V
  • Supports QWERTY Keypad Operation Plus GPIO Expansion
  • 18 GPIOs Can Be Configured into Eight Inputs and Ten Outputs to
    Support an 8 × 10 Keypad Array (80 Buttons)
  • ESD Protection Exceeds JESD 22 on non-GPIO pins
    • 2000-V Human Body Model (A114-A)
    • 1000-V Charged Device Model (C101)
  • ±15kV Human Body Model High Voltage ESD (GPIO lines)
  • Low Standby (Idle) Current Consumption: 3 µA
  • Polling Current Drain 70 µA for One Key Pressed
  • 10 Byte FIFO to Store 10 Key Presses and Releases
  • Supports 1-MHz Fast Mode Plus I2C Bus
  • Open-Drain Active-Low Interrupt Output, Asserted when
    Key is Pressed and Key is Released
  • Minimum Debounce Time of 50 µs
  • Schmitt-Trigger Action Allows Slow Input Transition and
    Better Switching Noise Immunity at the SCL and SDA Inputs:
    Typical Vhys at 1.8 V is 0.18 V
  • Latch-Up Performance Exceeds 200 mA Per JESD 78, Class II
  • Very Small Package
    • WCSP (YFP): 2 mm × 2 mm; 0.4 mm pitch
  • APPLICATIONS
    • Smart Phones
    • PDAs
Description

The TCA8418E is a keypad scan device with integrated ESD protection. It can operate from 1.65 V to 3.6 V and has 18 general purpose inputs/outputs (GPIO) that can be used to support up to 80 keys via the I2C interface [serial clock (SCL), serial data (SDA)].

The key controller includes an oscillator that debounces at 50 µs and maintains a 10 byte FIFO of key-press and release events which can store up to 10 keys with overflow wrap capability. An interrupt (INT) output can be configured to alert key presses and releases either as they occur, or at maximum rate. Also, for the YFP package, a CAD_INT pin is included to indicate the detection of CTRL-ALT-DEL (i.e., 1, 11, 21) key press action.

The major benefit of this device is it frees up the processor from having to scan the keypad for presses and releases.

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