SNVSBV0A June   2021  – June 2021 LM5146

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
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Custom Design With WEBENCH® Tools
        4. 9.2.1.4 Custom Design With Excel Quickstart Tool
        5. 9.2.1.5 Application Curves
      2. 9.2.2 Design 2 – High Density, 12-V, 8-A Rail From 48-V Telecom 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

9.2.1.2 Detailed Design Procedure

The design procedure for an LM5146 based regulator for a given application is streamlined by using the LM5146 Quickstart Calculator available as a free download, or by availing of TI's WEBENCH® Power Designer. Such tools are complemented by the availability of LM5145 and LM5146-Q1 evaluation module (EVM) designs, numerous PSPICE models, as well as several LM5146 reference designs populated in the TI Designs reference design library.

The selected buck converter powertrain components are cited in Table 9-6, and many of the components are available from multiple vendors. The MOSFETs in particular are chosen for both lowest conduction and switching power loss, as discussed in detail in Section 9.1.2.4.

The current limit setpoint in this design is set at 19 A based on the resistor RILIM and the 6-mΩ RDS(on) of the low-side MOSFET (typical at TJ = 25°C and VGS = 7.5 V). This design uses a low-DCR, metal-powder inductor, and all-ceramic output capacitor implementation.

Table 9-6 List of Materials for Application Circuit 1
REFERENCE DESIGNATORQTYSPECIFICATIONMANUFACTURERPART NUMBER
CIN64.7 µF, 100 V, X7S, 1210, ceramicTDKCGA6M3X7S2A475K200
MurataGCM32DC72A475KE02L
Taiyo YudenHMK325C7475MMHPE
COUT547 µF, 6.3 V, X7R, 1210, ceramicMurataGCM32ER70J476KE19L
Taiyo YudenJMK325B7476KMHTR
47 µF, 6.3 V, X7S, 1210, ceramicTDKCGA6P1X7S0J476M
LF13.3 µH, 6.25 mΩ, 19 A, 10.85 × 10.0 × 5.2 mmCyntecVCHA105D-3R3M
3.3 µH, 5.8 mΩ, 28.6 A, 10.5 × 10.0 × 6.5 mmTDKSPM10065VTT-3R3M-D
3.3 µH, 6.0 mΩ, 17 A, 10.9 × 10.0 × 6.0 mmPanasonicETQP6M3R3YLC
Q11100 V, 22 mΩ, MOSFET, SON 5 × 6OnsemiNVMFS6B25NL
Q21100 V, 6 mΩ, MOSFET, SON 5 × 6OnsemiFDWS86068-F085
U11Wide VIN synchronous buck controllerTexas InstrumentsLM5146RGYR