SCPS225C August   2011  – December 2017 TCA9509


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Description (continued)
  6. Pin Configuration or Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 I2C Interface Timing Requirements
  8. Parameter Measurement Information
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Two-Channel Bidirectional Buffer
      2. 9.3.2 Integrated A-Side Current Source
      3. 9.3.3 Standard Mode and Fast Mode Support
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. Clock Stretching Support
        2. VILC and Pulldown Strength Requirements
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Receiving Notification of Documentation Updates
    2. 13.2 Community Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information




  • Two-Channel Bidirectional Buffer
  • I2C Bus and SMBus Compatible
  • Operating Supply Voltage Range of
    2.7 V to 5.5 V on B side
  • Operating Voltage Range of 0.9 V to 5.5 V on
  • Voltage-Level Translation From
    0.9 V to 5.5 V and 2.7 V to 5.5 V
  • Active-High Repeater-Enable Input
  • Requires No External Pullup Resistors on
    Lower-Voltage Port-A
  • Open-Drain I2C I/O
  • 5.5-V Tolerant I2C and Enable Input Support Mixed-Mode Signal Operation
  • Lockup-Free Operation
  • Accommodates Standard Mode and Fast Mode I2C Devices and Multiple Masters
  • Supports Arbitration and Clock Stretching Across Repeater
  • Powered-Off High-Impedance I2C Bus Pins
  • Supports 400-kHz Fast I2C Bus Operating Speeds
  • Available in
    • 1.6-mm × 1.6-mm, 0.4-mm height, 0.5-mm Pitch QFN Package
    • 3-mm × 3-mm Industry Standard MSOP Package
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 1000-V Charged-Device Model (C101)


  • Servers
  • Routers (Telecom Switching Equipment)
  • Industrial Equipment
  • Products with many I2C slaves and/or long PCB Traces


This TCA9509 integrated circuit is an I2C bus/SMBus Repeater for use in I2C/SMBus systems. It can also provide bidirectional voltage-level translation (up-translation/down-translation) between low voltages (down to 0.9 V) and higher voltages (2.7 V to 5.5 V) in mixed-mode applications. This device enables I2C and similar bus systems to be extended, without degradation of performance even during level shifting.

The TCA9509 buffers both the serial data (SDA) and the serial clock (SCL) signals on the I2C bus, thus allowing 400-pF bus capacitance on the B-side. This device can also be used to isolate two halves of a bus for voltage and capacitance.

The TCA9509 has two types of drivers – A-side drivers and B-side drivers. All inputs and B-side I/Os are overvoltage tolerant to 5.5 V. The A-side I/Os are overvoltage tolerant to 5.5 V when the device is unpowered (VCCB and/or VCCA = 0 V).

Device Information(1)

TCA9509 VSSOP (8) 3.00 mm × 3.00 mm
X2QFN (8) 1.60 mm × 1.60 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Simplified Schematic

TCA9509 typ_app_cps225.gif

Revision History

Changes from B Revision (January 2012) to C Revision

  • Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section.Go
  • Added junction temperature to the Absolute Maximum RatingsGo
  • Changed thermal information for RVH and DGK packages Go
  • Changed VILC, added Test Conditions with new MIN and TYP values in the Electrical Characteristics tableGo
  • Updated Bus A (0.9-V to 5.5-V Bus) WaveformGo
  • Updated Bus B (2.7-V to 5.5-V Bus) WaveformGo

Changes from A Revision (October 2011) to B Revision

  • Added DGK package and package information to datasheet. Go

Changes from * Revision (August 2011) to A Revision

  • Corrected VCCA operating voltage lower limit, to 0.9V at multiple instances in document.Go
  • Changed Operating Supply Voltage Range value error in FEATURES for B side. Changed from (0.9 V to 5.5 V on B side) to (2.7 V to 5.5 V on B side).Go
  • Changed Operating Voltage Range value error in FEATURES for A side. Changed (2.7 V to VCCB – 1 V on A side) to (0.9 V to VCCB – 1 V on A side).Go