JAJSSU0 August   2024 LMR51440-Q1 , LMR51450-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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 System Characteristics
    7. 6.7 Typical Characteristics
  8. 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 Output Voltage
      3. 7.3.3  Enable
      4. 7.3.4  Switching Frequency
      5. 7.3.5  Power-Good Flag Output
      6. 7.3.6  Minimum ON-Time, Minimum OFF-Time, and Frequency Foldback
      7. 7.3.7  Bootstrap Voltage
      8. 7.3.8  Overcurrent and Short-Circuit Protection
      9. 7.3.9  Soft Start
      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 (PFM Version)
      5. 7.4.5 Light-Load Operation (FPWM Version)
  9. 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 Output Voltage Set-Point
        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 Input Capacitor Selection
        7. 8.2.2.7 Bootstrap Capacitor
        8. 8.2.2.8 Undervoltage Lockout Setpoint
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Compact Layout for EMI Reduction
        2. 8.4.1.2 Feedback Resistors
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 Custom Design With WEBENCH® Tools
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 ドキュメントの更新通知を受け取る方法
    4. 9.4 サポート・リソース
    5. 9.5 Trademarks
    6. 9.6 静電気放電に関する注意事項
    7. 9.7 用語集
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Tape and Reel Information

8.2 Typical Application

The LMR514x0-Q1 only requires a few external components to convert from a wide voltage range supply to a fixed output voltage. Figure 8-1 shows a basic schematic.

LMR51440-Q1 LMR51450-Q1 Application CircuitFigure 8-1 Application Circuit

The external components have to fulfill the needs of the application and the stability criteria of the control loop of the device. Use the following tables to simplify the output filter component selection.

Table 8-1 L and COUT Typical Values for LMR51440-Q1
fSW (kHz)VOUT (V)L (µH)COUT (µF) (1)RFBT (kΩ)RFBB (kΩ)CFF (pF)RFF (kΩ)
4403.34.72 × 4710031.6331
55.62 × 3310019.1331
128.22 × 101007.15331

1000

3.3

2.2

47 10031.6221

5

2.7

3310019.1221
(1) A ceramic capacitor is used in this table. All the COUT values are after derating.
Table 8-2 L and COUT Typical Values for LMR51450-Q1
fSW (kHz)VOUT (V)L (µH)COUT (µF) (1)RFBT (kΩ)RFBB (kΩ)CFF (pF)RFF (kΩ)
4403.33.32 × 4710031.6331
54.72 × 3310019.1331
12

8.2

2 × 151007.15331
(1) A ceramic capacitor is used in this table. All the COUT values are after derating.