SLVSD38C November   2015  – August 2021 TPS61089

PRODMIX  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and 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 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Undervoltage Lockout (UVLO)
      2. 8.3.2 Enable and Disable
      3. 8.3.3 Soft Start
      4. 8.3.4 Adjustable Switching Frequency
      5. 8.3.5 Adjustable Peak Current Limit
      6. 8.3.6 Overvoltage Protection
      7. 8.3.7 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operation
        1. 8.4.1.1 Forced PWM Mode
        2. 8.4.1.2 PFM Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Setting Switching Frequency
        3. 9.2.2.3 Setting Peak Current Limit
        4. 9.2.2.4 Setting Output Voltage
        5. 9.2.2.5 Inductor Selection
        6. 9.2.2.6 Input Capacitor Selection
        7. 9.2.2.7 Output Capacitor Selection
        8. 9.2.2.8 Loop Stability
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
      1. 11.2.1 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. 12.1.2.1 Custom Design With WEBENCH® Tools
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2.3 Setting Peak Current Limit

The peak input current is set by selecting the correct external resistor value correlating to the required current limit. Use Equation 4 to calculate the correct resistor value:

Equation 4. GUID-19C0394C-DE7B-4331-BBDC-856B491DC1B6-low.gif

where

  • RILIM is the resistance connected between the ILIM pin and ground
  • ILIM is the switching peak current limit

For a typical current limit of 8 A, the resistor value is 127 kΩ. Considering the device variation and the tolerance over temperature, the minimum current limit at the worst case can be 0.8 A lower than the value calculated by Equation 4. The minimum current limit must be higher than the required peak switch current at the lowest input voltage and the highest output power to make sure the TPS61089x does not hit the current limit and still can regulate the output voltage in these conditions.