SLVSI72A April   2025  – October 2025 TPS55285

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 Recommended Operating Conditions
    3. 5.3 Thermal Information
    4. 5.4 Electrical Characteristics
    5. 5.5 I2C Timing Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  VCC Power Supply
      2. 6.3.2  Default Output Enable(OE) bit Status
      3. 6.3.3  Input Undervoltage Lockout
      4. 6.3.4  Enable and Programmable UVLO
      5. 6.3.5  Soft Start
      6. 6.3.6  Shutdown and Load Discharge
      7. 6.3.7  Switching Frequency
      8. 6.3.8  Switching Frequency Dithering
      9. 6.3.9  Inductor Current Limit
      10. 6.3.10 Internal Charge Path
      11. 6.3.11 Output Voltage Setting
      12. 6.3.12 Output Current Limit
      13. 6.3.13 Output Cable Voltage Drop Compensation
      14. 6.3.14 Input Overvoltage Protection
      15. 6.3.15 Output Overvoltage Protection
      16. 6.3.16 Output Short Circuit Protection
      17. 6.3.17 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 PWM Mode
      2. 6.4.2 Power Save Mode
    5. 6.5 Programming
      1. 6.5.1 Data Validity
      2. 6.5.2 START and STOP Conditions
      3. 6.5.3 Byte Format
      4. 6.5.4 Acknowledge (ACK) and Not Acknowledge (NACK)
      5. 6.5.5 Target Address and Data Direction Bit
      6. 6.5.6 Single Read and Write
      7. 6.5.7 Multi-Read and Multi-Write
  8. 7 Register Maps
    1. 7.1 REF Register (Address = 0h, 1h) [reset = 10100100b, 00000001b]
    2. 7.2 IOUT_LIMIT Register (Address = 2h) [reset = 11100100b]
    3. 7.3 VOUT_SR Register (Address = 3h) [reset = 00000001b]
    4. 7.4 VOUT_FS Register (Address = 4h) [reset = 00000011b]
    5. 7.5 CDC Register (Address = 5h) [reset = 11110000b]
    6. 7.6 MODE Register (Address = 6h) [reset = 00100000b]
    7. 7.7 STATUS Register (Address = 7h) [reset = 00000001b]
    8. 7.8 Register Summary
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Switching Frequency
        2. 8.2.2.2 Output Voltage Setting
        3. 8.2.2.3 Inductor Selection
        4. 8.2.2.4 Input Capacitor
        5. 8.2.2.5 Output Capacitor
        6. 8.2.2.6 Output Current Limit
        7. 8.2.2.7 Loop Stability
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 Development Support
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

6.5.4 Acknowledge (ACK) and Not Acknowledge (NACK)

The acknowledge takes place after every byte. The acknowledge bit allows the receiver to signal the transmitter that the byte was successfully received and another byte is sent. All clock pulses, including the acknowledge 9th clock pulse, are generated by the controller.

The transmitter releases the SDA line during the acknowledge clock pulse so the receiver is allowed to pull the SDA line to low level and it remains stable low level during the high level period of this clock pulse.

The Not Acknowledge signal is when SDA remains high level during the 9th clock pulse. The controller then generates either a STOP to abort the transfer or a repeated START to start a new transfer.