SLVSD01B September   2015  – May 2019 TPS57140-EP

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Efficiency vs Load Current
  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  Fixed Frequency PWM Control
      2. 7.3.2  Slope-Compensation Output Current
      3. 7.3.3  Bootstrap Voltage (Boot)
      4. 7.3.4  Low-Dropout Operation
      5. 7.3.5  Error Amplifier
      6. 7.3.6  Voltage Reference
      7. 7.3.7  Adjusting the Output Voltage
      8. 7.3.8  Enable and Adjusting UVLO
      9. 7.3.9  Slow-Start or Tracking Pin (SS/TR)
      10. 7.3.10 Overload Recovery Circuit
      11. 7.3.11 Constant Switching Frequency and Timing Resistor (RT/CLK Pin)
      12. 7.3.12 Overcurrent Protection and Frequency Shift
      13. 7.3.13 Selecting the Switching Frequency
      14. 7.3.14 How to Interface to RT/CLK Pin
      15. 7.3.15 Power Good (PWRGD Pin)
      16. 7.3.16 Overvoltage Transient Protection (OVTP)
      17. 7.3.17 Thermal Shutdown
      18. 7.3.18 Small-Signal Model for Loop Response
      19. 7.3.19 Simple Small-Signal Model for Peak-Current-Mode Control
      20. 7.3.20 Small-Signal Model for Frequency Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sequencing
      2. 7.4.2 Pulse-Skip Eco-mode Control Scheme
  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  Selecting the Switching Frequency
        2. 8.2.2.2  Output Inductor Selection (LO)
        3. 8.2.2.3  Output Capacitor
        4. 8.2.2.4  Catch Diode
        5. 8.2.2.5  Input Capacitor
        6. 8.2.2.6  Slow-Start Capacitor
        7. 8.2.2.7  Bootstrap Capacitor Selection
        8. 8.2.2.8  UVLO Set Point
        9. 8.2.2.9  Output Voltage and Feedback Resistors Selection
        10. 8.2.2.10 Compensation
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Power-Dissipation Estimate
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.5 Error Amplifier

The TPS57140-EP has a transconductance amplifier for the error amplifier. The error amplifier compares the VSENSE voltage to the lower of the SS/TR pin voltage or the internal 0.8-V voltage reference. The transconductance (gm) of the error amplifier is 97 μS during normal operation. During the slow-start operation, the transconductance is a fraction of the normal operating gm. When the voltage of the VSENSE pin is below 0.8 V and the device is regulating using the SS/TR voltage, the gm is 25 μS.

The frequency-compensation components (capacitor, series resistor, and capacitor) are added from the COMP pin to ground.