SNVSBU9A June   2021  – June 2021 LM5145-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
    1. 6.1 Wettable Flanks
  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 Switching Characteristics
    7. 7.7 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  Input Range (VIN)
      2. 8.3.2  Output Voltage Setpoint and Accuracy (FB)
      3. 8.3.3  High-Voltage Bias Supply Regulator (VCC)
      4. 8.3.4  Precision Enable (EN/UVLO)
      5. 8.3.5  Power Good Monitor (PGOOD)
      6. 8.3.6  Switching Frequency (RT, SYNCIN)
        1. 8.3.6.1 Frequency Adjust
        2. 8.3.6.2 Clock Synchronization
      7. 8.3.7  Configurable Soft Start (SS/TRK)
        1. 8.3.7.1 Tracking
      8. 8.3.8  Voltage-Mode Control (COMP)
      9. 8.3.9  Gate Drivers (LO, HO)
      10. 8.3.10 Current Sensing and Overcurrent Protection (ILIM)
      11. 8.3.11 OCP Duty Cycle Limiter
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
      4. 8.4.4 Diode Emulation Mode
      5. 8.4.5 Thermal Shutdown
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Design and Implementation
      2. 9.1.2 Power Train Components
        1. 9.1.2.1 Inductor
        2. 9.1.2.2 Output Capacitors
        3. 9.1.2.3 Input Capacitors
        4. 9.1.2.4 Power MOSFETs
      3. 9.1.3 Control Loop Compensation
      4. 9.1.4 EMI Filter Design
    2. 9.2 Typical Applications
      1. 9.2.1 Design 1 – 12-A High-Efficiency Synchronous Buck DC/DC Regulator for Automotive Applications
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 9.2.1.2.2 Custom Design With Excel Quickstart Tool
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Design 2 – High Density, 12-V, 8-A Rail From 48-V Automotive Battery Power
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Power Stage Layout
      2. 11.1.2 Gate Drive Layout
      3. 11.1.3 PWM Controller Layout
      4. 11.1.4 Thermal Design and Layout
      5. 11.1.5 Ground Plane Design
    2. 11.2 Layout Example
  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 Documentation Support
      1. 12.2.1 Related Documentation
        1. 12.2.1.1 PCB Layout Resources
        2. 12.2.1.2 Thermal Design Resources
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.1.3 Application Curves

GUID-70B26539-6F63-4410-A41F-AF2988F96223-low.gifFigure 9-6 Efficiency and Power Loss vs IOUT and VIN
GUID-F90ACE48-B722-477B-A6D8-A13A62054056-low.gif
VIN step to 48 V 0.8-Ω Load
Figure 9-8 Start-Up, Resistive Load
GUID-F2E5F770-0F4E-439E-BCEF-2BE548F0B471-low.gif
VIN = 48 V 0.8-Ω Load
Figure 9-10 ENABLE ON, Resistive Load
GUID-6AAA6961-F940-4E41-B1E0-24D884641384-low.gif
VIN = 48 V
Figure 9-12 Load Transient Response, 0 A to 12 A to 0 A
GUID-4BB91743-D37D-4414-9F33-B7AA9557971D-low.gif
IOUT = 6 A
Figure 9-14 Line Transient Response, 85 V to 12 V
GUID-907597F0-9FA4-4ACD-8D89-581C33D52D1A-low.gif
VIN = 48 V IOUT = 6 A
Figure 9-7 SYNCOUT and SW Node Voltages
GUID-480E34D0-EDA9-473A-887D-3F3C8AEACF0C-low.gif
VIN 48 V to 6 V 0.8-Ω Load
Figure 9-9 Shutdown Through UVLO
GUID-D494B427-3060-4376-9E33-715D6BEBC86E-low.gif
VIN = 48 V
Figure 9-11 Load Transient Response, 6 A to 12 A to 6 A
GUID-D5940161-94B1-4701-ABDA-4EAE4D43FB25-low.gif
IOUT = 6 A
Figure 9-13 Line Transient Response, 12 V to 85 V
GUID-05D0B251-CC77-4D68-9E90-8CB668BEEDEA-low.gif
VIN = 48 V IOUT = 0 A
Figure 9-15 SW Node and Output Ripple Voltages