SNVSAV8B June   2017  – August 2020 LMR23615

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  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 Timing Characteristics
    7. 6.7 Switching Characteristics
    8. 6.8 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, Peak-Current-Mode Control
      2. 7.3.2  Adjustable Frequency
      3. 7.3.3  Adjustable Output Voltage
      4. 7.3.4  Enable/Sync
      5. 7.3.5  VCC, UVLO
      6. 7.3.6  Minimum ON-Time, Minimum-OFF Time, and Frequency Foldback at Dropout Conditions
      7. 7.3.7  Internal Compensation and CFF
      8. 7.3.8  Bootstrap Voltage (BOOT)
      9. 7.3.9  Overcurrent and Short-Circuit Protection
      10. 7.3.10 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
      3. 7.4.3 CCM Mode
      4. 7.4.4 Light Load Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Output Voltage Setpoint
        3. 8.2.2.3  Switching Frequency
        4. 8.2.2.4  Inductor Selection
        5. 8.2.2.5  Output Capacitor Selection
        6. 8.2.2.6  Feedforward Capacitor
        7. 8.2.2.7  Input Capacitor Selection
        8. 8.2.2.8  Bootstrap Capacitor Selection
        9. 8.2.2.9  VCC Capacitor Selection
        10. 8.2.2.10 Undervoltage Lockout Setpoint
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout for EMI Reduction
      2. 10.1.2 Ground Plane and Thermal Considerations
      3. 10.1.3 Feedback Resistors
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.2 Output Voltage Setpoint

The output voltage of LMR23615 is externally adjustable using a resistor divider network. The divider network is comprised of top feedback resistor RFBT and bottom feedback resistor RFBB. Equation 11 is used to determine the output voltage:

Equation 11. GUID-240873D8-319C-40D3-94FE-F73B3E29BBE0-low.gif

For example, choosing the value of RFBB as 22.1 kΩ, the desired output voltage set to 5 V, and the VREF = 1 V, the RFBB value is calculated using Equation 11. The formula yields to a value 88.7 kΩ.