SLVSCE9D June   2014  – October  2017 TPS25942A , TPS25942L , TPS25944A , TPS25944L

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Enable and Adjusting Undervoltage Lockout
      2. 9.3.2  Overvoltage Protection (OVP)
      3. 9.3.3  Hot Plug-In and In-Rush Current Control
      4. 9.3.4  Overload and Short Circuit Protection
        1. 9.3.4.1 Overload Protection
        2. 9.3.4.2 Short Circuit Protection
        3. 9.3.4.3 Start-Up With Short on Output
        4. 9.3.4.4 Constant Current Limit Behavior During Overcurrent Faults
      5. 9.3.5  Reverse Current Protection
      6. 9.3.6  FAULT Response
      7. 9.3.7  Current Monitoring
      8. 9.3.8  Power Good Comparator
      9. 9.3.9  IN, OUT and GND Pins
      10. 9.3.10 Thermal Shutdown
    4. 9.4 Device Functional Modes
      1. 9.4.1 Diode Mode
      2. 9.4.2 Shutdown Control
      3. 9.4.3 Operational Differences Between the TPS25942 and TPS25944
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Step by Step Design Procedure
        2. 10.2.2.2 Programming the Current-Limit Threshold: R(ILIM) Selection
        3. 10.2.2.3 Undervoltage Lockout and Overvoltage Set Point
        4. 10.2.2.4 Programming Current Monitoring Resistor—RIMON
        5. 10.2.2.5 Setting Output Voltage Ramp Time (tdVdT)
          1. 10.2.2.5.1 Case1: Start-Up Without Load: Only Output Capacitance C(OUT) Draws Current During Start-Up
          2. 10.2.2.5.2 Case 2: Start-Up With Load: Output Capacitance C(OUT) and Load Draws Current During Start-Up
        6. 10.2.2.6 Programing the Power Good Set Point
        7. 10.2.2.7 Support Component Selections—R6, R7 and CIN
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
      1. 10.3.1 Active ORing (Auto-Power Multiplexer) Operation
        1. 10.3.1.1 N+1 Power Supply Operation
        2. 10.3.1.2 Priority Power MUX Operation
        3. 10.3.1.3 Priority MUXing With Almost Equal Rails (VIN1 ~ VIN2)
        4. 10.3.1.4 Reverse Polarity Protection
  11. 11Power Supply Recommendations
    1. 11.1 Transient Protection
    2. 11.2 Output Short-Circuit Measurements
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Related Links
    4. 13.4 Receiving Notification of Documentation Updates
    5. 13.5 Community Resources
    6. 13.6 Trademarks
    7. 13.7 Electrostatic Discharge Caution
    8. 13.8 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.3.4.2 Short Circuit Protection

During a transient short circuit event, the current through the device increases very rapidly. As current-limit amplifier cannot respond quickly to this event due to its limited bandwidth, the device incorporates a fast-trip comparator, with a threshold I(FASTRIP). This comparator shuts down the pass device within 1 µs, when the current through internal FET exceeds I(FASTRIP) (I(OUT) > I(FASTRIP)), and terminates the rapid short-circuit peak current. The trip threshold is set to more than 50% of the programmed overload current limit (I(FASTRIP) = 1.5 × I(LIM) + 0.375). The fast-trip circuit holds the internal FET off for only a few microseconds, after which the device turns back on slowly, allowing the current-limit loop to regulate the output current to I(LIM). Then, device behaves similar to overload condition. Figure 67 through Figure 69 illustrate the behavior of the system when the current exceeds the fast-trip threshold.