SLVSDT1C July   2017  – June 2020 TPSM82480

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application space
      2.      Efficiency vs Output Current space space
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Enable and Shutdown (EN)
      2. 7.3.2  Soft-Start (SS), Pre-biased Output
      3. 7.3.3  Tracking (TR)
      4. 7.3.4  Output Voltage Select (VSEL)
      5. 7.3.5  Forced PWM (MODE)
      6. 7.3.6  Power Good (PG)
      7. 7.3.7  Thermal Good (TG)
      8. 7.3.8  Active Output Discharge
      9. 7.3.9  Undervoltage Lockout (UVLO)
      10. 7.3.10 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Pulse Width Modulation (PWM) Operation
      2. 7.4.2 Power Save Mode (PSM) Operation
      3. 7.4.3 Minimum Duty Cycle and 100% Mode Operation
      4. 7.4.4 Phase Shifted Operation
      5. 7.4.5 Phase Add/Shed and Current Balancing
      6. 7.4.6 Current Limit and Short Circuit Protection
  8. 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 Setting the Output Voltage
        2. 8.2.2.2 Setting VOUT2 Using the VSEL Feature
        3. 8.2.2.3 Feedforward Capacitance
        4. 8.2.2.4 Output Capacitor Selection
        5. 8.2.2.5 Input Capacitor Selection
        6. 8.2.2.6 Soft-Start Capacitor Selection
        7. 8.2.2.7 Tracking
        8. 8.2.2.8 Thermal Good
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

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

7.3.2 Soft-Start (SS), Pre-biased Output

The internal soft-start circuit controls the output voltage slope during startup. This avoids excessive inrush current and provides an adjustable controlled output-voltage rise time. The soft-start period also prevents unwanted voltage drop from high impedance power sources or batteries.

When EN is set to start device operation, the device starts switching after a delay of typically 200 µs and VOUT rises with a slope, controlled by the external capacitor which is connected to the SS/TR pin (soft start). Leaving the SS/TR pin floating or connecting to VIN provides internally set fastest startup with a soft-start slope of approxiimately 80 µs. See Application Curves for typical startup operation.

The device can start into a pre-biased output. In this case, the device starts switching, only when the internal set point for VOUT increases above the pre-biased voltage level.