SCPS226C January   2011  – August 2018 TCA4311A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Rise-Time Accelerators
      2. 8.3.2 READY Digital Output
      3. 8.3.3 EN Low Current Disable
    4. 8.4 Device Functional Modes
      1. 8.4.1 Start-Up
      2. 8.4.2 Connection Circuitry
      3. 8.4.3 Missing ACK Event
        1. 8.4.3.1 System Impact
        2. 8.4.3.2 System Workaround
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Input to Output Offset Voltage
        2. 9.2.1.2 Propagation Delays
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Resistor Pull-Up Value Selection
      3. 9.2.3 Application Curves
      4. 9.2.4 Live Insertion and Capacitance Buffering CompactPCI Application
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedure
        3. 9.2.4.3 Application Curves
      5. 9.2.5 Live Insertion and Capacitance Buffering PCI Application
        1. 9.2.5.1 Design Requirements
        2. 9.2.5.2 Detailed Design Procedure
        3. 9.2.5.3 Application Curves
      6. 9.2.6 Repeater/Bus Extender Application
        1. 9.2.6.1 Design Requirements
        2. 9.2.6.2 Detailed Design Procedure
        3. 9.2.6.3 Application Curves
      7. 9.2.7 Systems With Disparate Supply Voltages
        1. 9.2.7.1 Design Requirements
        2. 9.2.7.2 Detailed Design Procedure
        3. 9.2.7.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

3 Description

The TCA4311A is a hot-swappable I2C bus buffer that supports I/O card insertion into a live backplane without corruption of the data and clock busses. Control circuitry prevents the backplane from being connected to the card until a stop command or bus idle occurs on the backplane without bus contention on the card. When the connection is made, this device provides bidirectional buffering, keeping the backplane and card capacitances isolated. During insertion, the SDA and SCL lines are pre-charged to 1 V to minimize the current required to charge the parasitic capacitance of the chip.

When the I2C bus is idle, the TCA4311A can be put into shutdown mode by setting the EN pin low. When EN is high, the TCA4311A resumes normal operation. It also includes an open drain READY output pin, which indicates that the backplane and card sides are connected together. When READY is high, the SDAIN and SCLIN are connected to SDAOUT and SCLOUT. When the two sides are disconnected, READY is low.

Both the backplane and card may be powered with supply voltages ranging from 2.7 V to 5.5 V, with no restrictions on which supply voltage is higher.

The TCA4311A has standard open-drain I/Os. The size of the pull-up resistors to the I/Os depends on the system, but each side of this buffer must have a pull-up resistor. The device is designed to work with Standard Mode and Fast Mode I2C devices in addition to SMBus devices. Standard Mode I2C devices only specify 3 mA in a generic I2C system where Standard Mode devices and multiple masters are possible. Under certain conditions, high termination currents can be used.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
TCA4311A SOIC (8) 4.90 mm × 3.91 mm
VSSOP (8) 3.00 mm × 3.00 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.