SCPS239B June   2021  – October 2023 TCA39306-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Switching Characteristics (Translating Down)
    7. 5.7 Switching Characteristics (Translating Up)
    8. 5.8 Switching Characteristics
    9. 5.9 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
      1. 7.1.1 Definition of threshold voltage
      2. 7.1.2 Correct Device Set Up
      3. 7.1.3 Disconnecting a Target from the Main Bus Using the EN Pin
      4. 7.1.4 Supporting Remote Board Insertion to Backplane with TCA39306-Q1
      5. 7.1.5 Switch Configuration
      6. 7.1.6 Controller on Side 1 or Side 2 of Device
      7. 7.1.7 LDO and TCA39306-Q1 Concerns
      8. 7.1.8 Current Limiting Resistance on VREF2
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Enable (EN) Pin
      2. 7.3.2 Voltage Translation
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 General Applications of I2C
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Bidirectional Voltage Translation
        2. 8.2.2.2 Sizing Pullup Resistors
        3. 8.2.2.3 Bandwidth
      3. 8.2.3 Application Curve
    3. 8.3 Systems Examples: I3C Usage Considerations
      1. 8.3.1 I3C Bus Switching
      2. 8.3.2 I3C Bus Voltage Translation
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.1 I3C Bus Switching

Bus switching is when the bus path is enabled or disabled, but does not translate the bus voltage. External pull-up resistors are not needed for I3C, because the controller enables or disables the pull-up resistor on the SDA line. This presents a unique challenge for FET-based translators, like the TCA39306-Q1, because they rely on a pull-up resistor to pull the output side of the switch all the way to supply. For the switching use case, there is no translation, but the enable voltage must be high enough for the switch to stay on for the entire voltage range of the bus (0 V to bus voltage).

RON must be low enough for the full push-pull voltage range. The EN voltage must be at least 1 Vt (~0.6 V) above the maximum desired pass-voltage. This comes out to VEN ≥ VBUS + 0.6 V. Since the switch enable voltage is being directly controlled, the VREF1 and VREF2 pins are not needed, and can be shorted to ground to improve power consumption.

It is possible to control the EN pin with a voltage equal to VBUS, but external pull-up resistors on the downstream side are a requirement to ensure the bus is pulled entirely to VBUS.

GUID-20211209-SS0I-CDQ5-JHK2-CZ1PBZZWH45G-low.svg Figure 8-5 I3C Bus Switching Application (Without Pull-up Resistors)
GUID-20211209-SS0I-RVFT-VZ9P-GF3Q5XVHWGMX-low.svg Figure 8-6 I3C Bus Switching Application (With Pull-up Resistors)