ZHCSPC5 October   2022 LM51231-Q1

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Device Enable/Disable (EN, VH Pin)
      2. 7.3.2  High Voltage VCC Regulator (BIAS, VCC Pin)
      3. 7.3.3  Light Load Switching Mode Selection (MODE Pin)
      4. 7.3.4  VOUT Range Selection (RANGE Pin)
      5. 7.3.5  Line Undervoltage Lockout (UVLO Pin)
      6. 7.3.6  Fast Restart using VCC HOLD (VH Pin)
      7. 7.3.7  Adjustable Output Regulation Target (VOUT, TRK, VREF Pin)
      8. 7.3.8  Overvoltage Protection (VOUT Pin)
      9. 7.3.9  Power Good Indicator (PGOOD Pin)
      10. 7.3.10 Dynamically Programmable Switching Frequency (RT)
      11. 7.3.11 External Clock Synchronization (SYNC Pin)
      12. 7.3.12 Programmable Spread Spectrum (DITHER Pin)
      13. 7.3.13 Programmable Soft-start (SS Pin)
      14. 7.3.14 Wide Bandwidth Transconductance Error Amplifier and PWM (TRK, COMP Pin)
      15. 7.3.15 Current Sensing and Slope Compensation (CSP, CSN Pin)
      16. 7.3.16 Constant Peak Current Limit (CSP, CSN Pin)
      17. 7.3.17 Maximum Duty Cycle and Minimum Controllable On-time Limits
      18. 7.3.18 MOSFET Drivers, Integrated Boot Diode, and Hiccup Mode Fault Protection (LO, HO, HB Pin)
      19. 7.3.19 Thermal Shutdown Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Status
        1. 7.4.1.1 Shutdown Mode
        2. 7.4.1.2 Configuration Mode
        3. 7.4.1.3 Active Mode
        4. 7.4.1.4 Bypass Mode
          1. 7.4.1.4.1 Bypass DE mode
          2. 7.4.1.4.2 Bypass FPWM
      2. 7.4.2 Light Load Switching Mode
        1. 7.4.2.1 Forced PWM (FPWM) Mode
        2. 7.4.2.2 Diode Emulation (DE) Mode
        3. 7.4.2.3 Forced Diode Emulation Operation in FPWM Mode
  8. 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
      3. 8.2.3 Application Ideas
      4. 8.2.4 Application Curves
    3. 8.3 System Example
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 接收文档更新通知
    2. 9.2 支持资源
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 术语表
  10. 10Mechanical, Packaging, and Orderable Information

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

3 说明

LM51231-Q1 器件是一款采用峰值电流模式控制的宽输入范围同步升压控制器。该器件的宽输入范围支持汽车冷启动和负载突降。当 BIAS 引脚等于或大于 3.8V 时，最小输入电压可低至 0.8V。可使用跟踪功能对输出电压进行动态编程。当 VSUPPLY > VLOAD 时，会自动进入旁路模式运行，从而消除高侧 MOSFET 的体二极管压降。用户可通过外部电阻器对开关频率进行动态编程，编程范围为 100kHz 至 2.2MHz。2.2MHz 的开关频率可更大限度地降低 AM 频带干扰，并支持实现小解决方案尺寸和快速瞬态响应。

该器件具有内置的保护功能，例如在 VSUPPLY 范围内具有恒定的峰值电流限制、过压保护和热关断功能。外部时钟同步、可编程展频调制以及具有超低寄生效应的无引线封装有助于降低 EMI 并避免串扰问题。附加功能包括线路 UVLO、FPWM、二极管仿真、DCR 电感器电流检测、可编程的软启动和电源正常状态指示器

器件信息
器件型号封装(1)封装尺寸（标称值）
LM51231-Q1QFN (20)3.5mm x 3.5mm
(1) 要了解所有可用封装，请见数据表末尾的可订购产品附录。
GUID-7CFE2408-30BE-443F-92FE-79F6448B9772-low.gif典型应用