SNVSAP9A March   2017  – February 2018 LM25141-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  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 Switching Characteristics
    7. 6.7 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  High Voltage Start-Up Regulator
      2. 7.3.2  VCC Regulator
      3. 7.3.3  Oscillator
      4. 7.3.4  Synchronization
      5. 7.3.5  Frequency Dithering (Spread Spectrum)
      6. 7.3.6  Enable
      7. 7.3.7  Power Good
      8. 7.3.8  Output Voltage
        1. 7.3.8.1 Minimum Output Voltage Adjustment
      9. 7.3.9  Current Sense
      10. 7.3.10 DCR Current Sensing
      11. 7.3.11 Error Amplifier and PWM Comparator
      12. 7.3.12 Slope Compensation
      13. 7.3.13 Hiccup Mode Current Limiting
      14. 7.3.14 Standby Mode
      15. 7.3.15 Soft Start
      16. 7.3.16 Diode Emulation
      17. 7.3.17 High- and Low-Side Drivers
  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 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Inductor Calculation
        3. 8.2.2.3 Current Sense Resistor
        4. 8.2.2.4 Output Capacitor
        5. 8.2.2.5 Input Filter
          1. 8.2.2.5.1 EMI Filter Design
          2. 8.2.2.5.2 MOSFET Selection
          3. 8.2.2.5.3 Driver Slew Rate Control
          4. 8.2.2.5.4 Frequency Dithering
        6. 8.2.2.6 Control Loop
          1. 8.2.2.6.1 Feedback Compensator
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Layout Procedure
    2. 10.2 Layout Examples
  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 Documentation Support
      1. 11.2.1 Related Documentation
        1. 11.2.1.1 PCB Layout Resources
        2. 11.2.1.2 Thermal Design Resources
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.1 Overview

The LM25141-Q1 is a switching controller which features all of the functions necessary to implement a high efficiency buck power supply that can operate over a wide input voltage range. The LM25141-Q1 is configured to provide a single fixed 3.3-V, or 5-V output, or an adjustable output between 1.5 V to 15 V. This easy to use controller integrates high-side and low-side MOSFET drivers capable of sourcing 3.25 A and sinking 4.25 A peak. The control method is current mode control which provides inherent line feed-forward, cycle-by-cycle current limiting, and ease of loop compensation. With the OSC pin connected to VDD, the default oscillator frequency is 2.2 MHz. With the OSC pin grounded, the oscillator frequency is 440 kHz. The LM25141-Q1 can be synchronized by applying an external clock to the DEMB pin. Fault protection features include current limiting, thermal shutdown, and remote shutdown capability.

The LM25141-Q1 incorporates features that simplify compliance with the CISPR and automotive EMI requirements. The LM25141-Q1 has optional spread spectrum to reduce the peak EMI and gate drivers with slew rate control. The VQFN-24 package features an exposed pad to aid in thermal dissipation.