I2C Controlled Keypad Scan 25-Pin DSBGA T/R

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. This provides power and bandwidth savings. The TCA8418E is also ideal for usage with processors that have limited GPIOs.

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 V_hys 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
• GPS Devices
• MP3 Players
• Digital Cameras