SLVSC97B March   2014  – September 2020 TPS2556-Q1 , TPS2557-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Application
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Terminal Configuration and Functions
    1.     Terminal Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Handling Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Switching Characteristics
    7. 7.7 Typical Characteristics
      1.      16
        1.       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 Overcurrent Conditions
      2. 8.3.2 FAULT Response
      3. 8.3.3 Thermal Sense
    4. 8.4 Device Functional Modes
      1. 8.4.1 Undervoltage Lockout (UVLO)
      2. 8.4.2 Enable ( EN OR EN)
      3. 8.4.3 Auto-Retry Functionality
      4. 8.4.4 Two-Level Current-Limit Circuit
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application, Design for Current Limit
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Determine Design Parameters
        2. 9.2.2.2 Programming the Current-Limit Threshold
        3. 9.2.2.3 Selecting Current-Limit Resistor 1
        4. 9.2.2.4 Selecting Current-Limit Resistor 2
        5. 9.2.2.5 Accounting for Resistor Tolerance
        6. 9.2.2.6 Power Dissipation and Junction Temperature
      3. 9.2.3 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 Related Links
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.3 Thermal Sense

The TPS2556-Q1 and TPS2557-Q1 devices self-protect by using two independent thermal sensing circuits that monitor the operating temperature of the power switch and disable operation if the temperature exceeds recommended operating conditions. The TPS2556-Q1 and TPS2557-Q1 devices operate in constant-current mode during an overcurrent condition, which increases the voltage drop across power switch. The power dissipation in the package is proportional to the voltage drop across the power switch, which increases the junction temperature during an overcurrent condition. The first thermal sensor (OTSD) turns off the power switch when the die temperature exceeds 135°C (min) and the part is in current limit. Hysteresis is built into the thermal sensor, and the switch turns on after the device has cooled approximately 20°C.

The TPS2556-Q1 and TPS2557-Q1 devices also have a second thermal sensor (OTSD2). This thermal sensor turns off the power switch when the die temperature exceeds 155°C (minimum) regardless of whether the power switch is in current limit, and turns on the power switch after the device has cooled approximately 20°C. The TPS2556-Q1 and TPS2557-Q1 devices continue to cycle off and on until the fault is removed.