SLVSEM3D May   2020  – September 2021 TPS25850-Q1 , TPS25851-Q1 , TPS25852-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Switching Characteristics
    8. 8.8 Typical Characteristics
  9. 9 Parameter Measurement Information
  10. 10Detailed Description
    1. 10.1 Overview
    2. 10.2 Functional Block Diagram
    3. 10.3 Feature Description
      1. 10.3.1  Power-Down or Undervoltage Lockout
      2. 10.3.2  Input Overvoltage Protection (OVP) - Continuously Monitored
      3. 10.3.3  Buck Converter
      4. 10.3.4  FREQ/SYNC
      5. 10.3.5  Bootstrap Voltage (BOOT)
      6. 10.3.6  Minimum ON-Time, Minimum OFF-Time
      7. 10.3.7  Internal Compensation
      8. 10.3.8  Selectable Output Voltage (VSET)
      9. 10.3.9  Current Limit and Short Circuit Protection
        1. 10.3.9.1 USB Switch Programmable Current Limit (ILIM)
        2. 10.3.9.2 Interlocking for Two-Level USB Switch Current Limit
        3. 10.3.9.3 Cycle-by-Cycle Buck Current Limit
        4. 10.3.9.4 OUT Current Limit
      10. 10.3.10 Cable Compensation
      11. 10.3.11 Thermal Management With Temperature Sensing (TS) and OTSD
      12. 10.3.12 Thermal Shutdown
      13. 10.3.13 USB Enable On/Off Control (TPS25852-Q1)
      14. 10.3.14 FAULT Indication (TPS25851-Q1 and TPS25852-Q1)
      15. 10.3.15 USB Specification Overview
      16. 10.3.16 USB Type-C® Basics
        1. 10.3.16.1 Configuration Channel
        2. 10.3.16.2 Detecting a Connection
        3. 10.3.16.3 Plug Polarity Detection (TPS25851-Q1)
      17. 10.3.17 USB Port Operating Modes
        1. 10.3.17.1 USB Type-C® Mode
        2. 10.3.17.2 Dedicated Charging Port (DCP) Mode (TPS25850-Q1 Only)
          1. 10.3.17.2.1 DCP BC1.2 and YD/T 1591-2009
          2. 10.3.17.2.2 DCP Divider-Charging Scheme
          3. 10.3.17.2.3 DCP 1.2-V Charging Scheme
        3. 10.3.17.3 DCP Auto Mode (TPS25850-Q1)
    4. 10.4 Device Functional Modes
      1. 10.4.1 Shutdown Mode
      2. 10.4.2 Active Mode
  11. 11Application and Implementation
    1. 11.1 Application Information
    2. 11.2 Typical Applications
      1. 11.2.1 Design Requirements
      2. 11.2.2 Detailed Design Procedure
        1. 11.2.2.1 Output Voltage Setting
        2. 11.2.2.2 Switching Frequency
        3. 11.2.2.3 Inductor Selection
        4. 11.2.2.4 Output Capacitor Selection
        5. 11.2.2.5 Input Capacitor Selection
        6. 11.2.2.6 Bootstrap Capacitor Selection
        7. 11.2.2.7 Undervoltage Lockout Set-Point
        8. 11.2.2.8 Cable Compensation Set-Point
      3. 11.2.3 Application Curves
  12. 12Power Supply Recommendations
  13. 13Layout
    1. 13.1 Layout Guidelines
    2. 13.2 Layout Example
    3. 13.3 Ground Plane and Thermal Considerations
  14. 14Device and Documentation Support
    1. 14.1 Receiving Notification of Documentation Updates
    2. 14.2 Support Resources
    3. 14.3 Trademarks
    4. 14.4 Electrostatic Discharge Caution
    5. 14.5 Glossary
  15. 15Mechanical, Packaging, and Orderable Information

12 Power Supply Recommendations

The input supply must be able to withstand the maximum input current and maintain a stable voltage. The resistance of the input supply rail must be low enough that an input current transient does not cause a high enough drop at the TPS2585x-Q1 supply voltage that it causes a false UVLO fault triggering and system reset. If the TPS2585x-Q1 is connected to the input supply through long wires or PCB traces, special care is required to achieve good performance. An additional bulk capacitance can be required in addition to the ceramic input capacitors. The amount of bulk capacitance is not critical, but a 100-μF electrolytic capacitor is a typical choice.

The input voltage must not be allowed to fall below the output voltage. In this scenario, such as a shorted input test, the output capacitors discharge through the internal parasitic diode found between the VIN and SW pins of the device. During this condition, the current can become uncontrolled, possibly causing damage to the device. If this scenario is considered likely, then a Schottky diode between the input supply and the output must be used.