ZHCSKA2A September   2019  – February 2020 LMR36520

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      效率与输出电流间的关系 VOUT = 5V，400kHz
      2.      简化原理图
  4. 4 修订历史记录
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  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 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 System Characteristics
    9. 7.9 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 Power-Good Flag Output
      2. 8.3.2 Enable and Start-up
      3. 8.3.3 Current Limit and Short Circuit
      4. 8.3.4 Undervoltage Lockout and Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Auto Mode
      2. 8.4.2 Forced PWM Operation
      3. 8.4.3 Dropout
      4. 8.4.4 Minimum Switch On-Time
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design 1: Low Power 24-V, 2-A Buck Converter
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1  Choosing the Switching Frequency
          2. 9.2.1.2.2  Setting the Output Voltage
          3. 9.2.1.2.3  Inductor Selection
          4. 9.2.1.2.4  Output Capacitor Selection
          5. 9.2.1.2.5  Input Capacitor Selection
          6. 9.2.1.2.6  CBOOT
          7. 9.2.1.2.7  VCC
          8. 9.2.1.2.8  CFF Selection
          9. 9.2.1.2.9  External UVLO
          10. 9.2.1.2.10 Maximum Ambient Temperature
      2. 9.2.2 Application Curves
    3. 9.3 What to Do and What Not to Do
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Ground and Thermal Considerations
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 器件支持
      1. 12.1.1 开发支持
    2. 12.2 文档支持
      1. 12.2.1 相关文档
    3. 12.3 接收文档更新通知
    4. 12.4 支持资源
    5. 12.5 商标
    6. 12.6 静电放电警告
    7. 12.7 Glossary
  13. 13机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

9.2.2 Application Curves

Unless otherwise specified, the following conditions apply: VIN = 24 V, TA = 25°C. Figure 32 shows the circuit with the appropriate BOM from Table 5.

LMR36520 Efficiency_LMR36520_3p3V_400kHz_6p8uH.gif
LMR36520A VOUT = 3.3 V 400 kHz
Figure 16. Efficiency
LMR36520 Efficiency_LMR36520_5V_400kHz_10uH.gif
LMR36520A VOUT = 5 V 400 kHz
Figure 18. Efficiency
LMR36520 Efficiency_LMR36520_12V_400kHz_33uH.gif
LMR36520A VOUT = 12 V 400 kHz
Figure 20. Efficiency
LMR36520 Dropout_LMR36520_5V.gif
VOUT = 5 V 400 kHz
Figure 22. Dropout Characteristic
LMR36520 VIN_IIN_Curve.gif
VOUT = 3.3 V IOUT = 0 A
Figure 24. Input Supply Current
LMR36520 EN_Startup_Waveform.gif
VIN = 24 V VOUT = 3.3 V ILOAD = 2 A
Figure 26. Enable Start-Up Waveform
LMR36520 LoadTransient_24V_3p3VOUT_0p5_2A.gif
VOUT = 3.3 V 400 kHz ILOAD = 0.5 A - 2 A
Slew Rate = 1 A/µs
Figure 28. Load Transient
LMR36520 OutputRipple24V_5Vout_NL.gif
VIN = 24 V VOUT = 5 V ILOAD = 0 A
Figure 30. Output Ripple at No load
LMR36520 LoadRegulation_LMR36520_3p3V_400kHz_6p8uH.gif
LMR36520A VOUT = 3.3 V 400 kHz
Figure 17. Load Regulation
LMR36520 LoadRegulation_LMR36520_5V_400kHz_10uH.gif
LMR36520A VOUT = 5 V 400 kHz
Figure 19. Load Regulation
LMR36520 LoadRegulation_LMR36520_12V_400kHz_33uH.gif
LMR36520A VOUT = 12 V 400 kHz
Figure 21. Load Regulation
LMR36520 Dropout_LMR36520_12Vout.gif
VOUT = 12 V 400 kHz
Figure 23. Dropout Characteristic
LMR36520 Iout_Iin_Curve.gif
VOUT = 3.3 V RFBT = 100 kΩ
Figure 25. Input Supply Current versus Load Current
LMR36520 EN_Shutdown_Waveform.gif
VIN = 24 V VOUT = 3.3 V ILOAD = 2 A
Figure 27. Enable Shutdown Waveform
LMR36520 LoadTransient_24V_5VOUT_0p5_2A.gif
VOUT = 5 V 400 kHz ILOAD = 0.5 A - 2 A
Slew Rate = 1 A/µs
Figure 29. Load Transient
LMR36520 OutputRipple24V_5Vout_1A.gif
VIN = 24 V VOUT = 5 V ILOAD = 1 A
Figure 31. Output Ripple at 1 A
LMR36520 Circuit_typical_apps_curve_20-ADJ-output.gifFigure 32. Circuit for Typical Application Curves

Table 5. BOM for Typical Application Curves

VOUT FREQUENCY L COUT RFBT RFBB CFF IC
3.3 V 400 kHz 6.8 µH, 29.45 mΩ 3 x 22 µF, 25V 46.4 kΩ 20.0 kΩ None LMR36520A
5 V 400 kHz 10 µH, 29.82 mΩ 2 x 22 µF, 25V 34.0 kΩ + 46.4 kΩ 20.0 kΩ None LMR36520A
12 V 400 kHz 33 µH, 57 mΩ 3 x 22 µF, 25V 100 kΩ 9.09 kΩ None LMR36520A