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  • Operating Power-Supply Voltage Range of 1.65V to 3.6V
  • Supports FM+ I2C Operation up to 1MHz
  • Can Support up to 128 (8x16) Key Scan
  • Internal Power-On-Reset
  • Open Drain Open Drain Active Low INT Output
  • Noise Filter on SCL/SDA and Inputs
  • Open Drain Outputs Can Sink up to 12mA Current for LED
  • Hardware Coded HID and REPORT Descriptors
  • Available With Preprogrammed Keyboard Map
  • Software Reset per HID Over I2C Standard
  • Internal Pull-up Resistors Make Implementation Easy
    With no Need for External Components
  • HID Over I2C Commands Supported
    • RESET
  • Fixed Length 8-byte INPUT Report can Detect up to 6
    Simultaneous Key Presses Excluding Modifiers (CTRL, ALT,
  • INPUT Report Generated on Key Press and Release
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 1000-V Human-Body Model (A114-A)

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This 128 key scan device is specifically targeted towards end equipment that runs on Windows 8 operating system. The device is fully compliant with the HID over I2C specification defined (ver 1.0) defined by Microsoft. The HID and report descriptors are hard coded into the device so that they don’t need to be programmed at production. The device also comes with a preprogrammed keyboard map that is compatible with most standard laptop/notebook keyboards. However, the device also available without a pre-programmed keyboard, so that any keyboard map may be written into it at production.

The device generates INPUT reports of standard 8-byte length with the 1st byte being the modifier byte. After the keyboard map is programmed into the device it automatically recognizes the row/column location of the modifier keys based on their usage code. It is capable of detecting and reporting up to six simultaneous key presses plus eight modifiers. It generates an input report on each key press and each key release.

The device also supports LED indicators that are standard on a keyboard. Different variations support 2,4 or 8 LED outputs. Each output has open drain architecture and is capable of sinking up to 12mA of current. The LEDs are controlled by a standard OUTPUT report as described in the HID over I2C standard.

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Technical documentation

= Top documentation for this product selected by TI
No results found. Please clear your search and try again. View all 7
Type Title Date
* Datasheet Low-Voltage 8x16 Keyboard Scanner With HID over I2C Compliant Interface datasheet Mar. 27, 2013
Selection guides I2C Infographic Flyer Dec. 03, 2015
Application notes Understanding the I2C Bus Jun. 30, 2015
Application notes Maximum Clock Frequency of I2C Bus Using Repeaters May 15, 2015
Application notes I2C Bus Pull-Up Resistor Calculation Feb. 13, 2015
Application notes OTP Creation Guide Mar. 27, 2013
User guides TCA8424 Evaluation Module User's Guide Feb. 22, 2013

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

document-generic User guide

The TCA8424 EVM showcases the capabilities and benefits of using the TCA8424 in a keyboard scanner application. This EVM is designed to allow the user to program their own OTPs and then test the OTP in a system use case.

  • Hid over I2C compliant Keyboard Scanner
  • Low power consumption
  • 512 byte OTP to configure keyboard map and drivers
    SCDC004.ZIP (223 KB)

    Software development

    FIRMWARE Download
    SCDC003.ZIP (78 KB)

    Design tools & simulation

    SCDM155.ZIP (61 KB) - IBIS Model
    PSpice® for TI design and simulation tool
    PSPICE-FOR-TI — PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
    • Leverages Cadence PSpice Technology
    • Preinstalled library with a suite of digital models to enable worst-case timing analysis
    • Dynamic updates ensure you have access to most current device models
    • Optimized for simulation speed without loss of accuracy
    • Supports simultaneous analysis of multiple products
    • (...)
    SPICE-based analog simulation program
    TINA-TI TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
    document-generic User guide
    DESIGN TOOLS Download
    I2C designer tool
    I2C-DESIGNER — Use the I2C Designer tool to quickly resolve conflicts in addressing, voltage level and frequency in I2C based designs. Enter master and slave inputs to automatically generate an I2C tree or easily build a custom solution. This tool will help designers save time and comply with the I2C standard with (...)
    • GUI-based web application
    • Exportable designs
    • JSON file uploader
    • Bill of materials generator

    CAD/CAE symbols

    Package Pins Download
    VQFN (RHA) 40 View options

    Ordering & quality

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