ZHCS584B March   2011  – June 2019 LM21212-2

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化应用电路
  4. 4 修订历史记录
  5. 5 说明（续）
  6. 6 Pin Configuration and Functions
    1.     Pin Descriptions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Ratings
    4. 7.4 Electrical Characteristics
    5. 7.5 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 Precision Enable
      2. 8.3.2 UVLO
      3. 8.3.3 Current Limit
      4. 8.3.4 Short-Circuit Protection
      5. 8.3.5 Thermal Protection
      6. 8.3.6 Power-Good Flag
      7. 8.3.7 Light Load Operation
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Typical Application 1
        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 Output Voltage
          3. 9.2.1.2.3 Precision Enable
          4. 9.2.1.2.4 Soft Start
          5. 9.2.1.2.5 Resistor-Adjustable Frequency
          6. 9.2.1.2.6 Inductor Selection
          7. 9.2.1.2.7 Output Capacitor Selection
          8. 9.2.1.2.8 Input Capacitor Selection
          9. 9.2.1.2.9 Control Loop Compensation
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Typical Application Schematic 2
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
  10. 10Layout
    1. 10.1 Layout Considerations
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 第三方产品免责声明
      2. 11.1.2 开发支持
        1. 11.1.2.1 使用 WEBENCH® 工具创建定制设计
    2. 11.2 接收文档更新通知
    3. 11.3 社区资源
    4. 11.4 商标
    5. 11.5 静电放电警告
    6. 11.6 Glossary
  12. 12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

7.5 Typical Characteristics

Unless otherwise specified: VVIN = 5 V, VOUT = 1.2 V, L= 0.56 µH (1.8-mΩ RDCR), CSS = 33 nF, fSW = 500 kHz (RADJ= 95.3 kΩ), TA = 25°C for efficiency curves, loop gain plots and waveforms, and TJ = 25°C for all others.
LM21212-2 30155153.gif
Figure 1. Efficiency
LM21212-2 30155177.gif
VOUT = 2.5 V FSW= 300 KHz Inductor P/N Ser2010-102MLD
Figure 3. Efficiency
LM21212-2 30155175.gif
Figure 5. Non-Switching IAVIN and IPVIN vs Temperature
LM21212-2 30155171.gif
Figure 7. Enable Threshold and Hysteresis vs Temperature
LM21212-2 30155173.gif
Figure 9. Enable Low Current vs Temperature
LM21212-2 30155172.gif
Figure 11. Minimum On-Time vs Temperature
LM21212-2 30155158.gif
Figure 13. Peak Current Limit vs Temperature
LM21212-2 30155166.gif
                                      200 µs/DIV
Figure 15. Start-up With SS/TRK Open Circuit
LM21212-2 30155180.gif
                                      10 µs/DIV
Figure 17. Output Overcurrent Condition
LM21212-2 30155156.gif
Figure 2. Efficiency
LM21212-2 30155157.gif
Figure 4. Non-Switching IQTOTAL vs VIN
LM21212-2 30155176.gif
Figure 6. VFB vs Temperature
LM21212-2 30155170.gif
Figure 8. UVLO Threshold and Hysteresis vs Temperature
LM21212-2 30155174.gif
Figure 10. OVP/UVP Threshold vs Temperature
LM21212-2 30155168.gif
Figure 12. FET Resistance vs Temperature
LM21212-2 30155163.gif
                                      2 ms/DIV
Figure 14. Start-up With Prebiased Output
LM21212-2 30155167.gif
                                      200 ms/DIV
Figure 16. Start-up With Applied Track Signal