ZHCSIN6C August   2018  – October 2019 LMR36015-Q1

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      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 System Characteristics
    8. 7.8 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
      5. 8.4.5 Spread Spectrum Operation
  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, 1.5-A PFM Converter
        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  Choosing the Switching Frequency
          3. 9.2.1.2.3  Setting the Output Voltage
            1. 9.2.1.2.3.1 FB for Adjustable Output
          4. 9.2.1.2.4  Inductor Selection
          5. 9.2.1.2.5  Output Capacitor Selection
          6. 9.2.1.2.6  Input Capacitor Selection
          7. 9.2.1.2.7  CBOOT
          8. 9.2.1.2.8  VCC
          9. 9.2.1.2.9  CFF Selection
            1. 9.2.1.2.9.1 External UVLO
          10. 9.2.1.2.10 Maximum Ambient Temperature
      2. 9.2.2 Application Curves
      3. 9.2.3 Design 2: High Density 12-V, 1.5-A FPWM Converter
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 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
        1. 12.1.1.1 使用 WEBENCH® 工具创建定制设计方案
    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

8.4.2 Forced PWM Operation

The following select variant(s) is/are a factory option made available for cases when constant frequency operation is more important than light load efficiency.

Table 1. LMR36015-Q1 Device Variants with Fixed Frequency Operation at No Load

ORDERABLE PART NUMBER OUTPUT VOLTAGE SPREAD SPECTRUM FPWM fSW
LMR36015FSCQRNXTQ1 Adjustable Yes Yes 2.1 MHz
LMR36015FSCQRNXRQ1 Adjustable Yes Yes 2.1 MHz
LMR36015FSC3RNXRQ1 3.3-V fixed Yes Yes 2.1 MHz
LMR36015FSC3RNXTQ1 3.3-V fixed Yes Yes 2.1 MHz

In FPWM operation, the diode emulation feature is turned off. This means that the device remains in CCM under light loads. Under conditions where the device must reduce the on-time or off-time below the ensured minimum to maintain regulation, the frequency reduces to maintain the effective duty cycle required for regulation. This occurs for very high and very low input/output voltage ratios. When in FPWM mode, a limited reverse current is allowed through the inductor allowing power to pass from the regulator’s output to its input. Note that in FPWM mode, larger currents pass through the inductor, if lightly loaded, than in auto mode. Once loads are heavy enough to necessitate CCM operation, FPWM mode has no measurable effect on regulator operation.