ZHCSQ27 October   2022 LM5012

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings_Catalog
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 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  Control Architecture
      2. 8.3.2  Internal VCC Regulator and Bootstrap Capacitor
      3. 8.3.3  Regulation Comparator
      4. 8.3.4  Internal Soft Start
      5. 8.3.5  On-Time Generator
      6. 8.3.6  Current Limit
      7. 8.3.7  N-Channel Buck Switch and Driver
      8. 8.3.8  Schottky Diode Selection
      9. 8.3.9  Enable and Undervoltage Lockout (EN/UVLO)
      10. 8.3.10 Power Good (PGOOD)
      11. 8.3.11 Thermal Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
      4. 8.4.4 Sleep Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Switching Frequency (RRON)
        3. 9.2.2.3 Buck Inductor (LO)
        4. 9.2.2.4 Schottky Diode (DSW)
        5. 9.2.2.5 Output Capacitor (COUT)
        6. 9.2.2.6 Input Capacitor (CIN)
        7. 9.2.2.7 Type 3 Ripple Network
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Compact PCB Layout for EMI Reduction
        2. 9.4.1.2 Feedback Resistors
      2. 9.4.2 Layout Example
        1. 9.4.2.1 Thermal Considerations
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 第三方产品免责声明
      2. 10.1.2 Development Support
        1. 10.1.2.1 Custom Design With WEBENCH® Tools
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 接收文档更新通知
    4. 10.4 支持资源
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 术语表
  11. 11Mechanical, Packaging, and Orderable Information

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8.1 Overview

The LM5012 is an easy-to-use, ultra-low IQ constant on-time (COT) non-synchronous step-down buck regulator. With an integrated high-side power MOSFET, the LM5012 is a low-cost, highly efficient buck converter that operates from a wide input voltage of 6 V to 100 V, delivering up to 2.5-ADC load current. The LM5012 is available in an 8-pin SO PowerPAD intergrated circuit package with 1.27-mm pin pitch for adequate spacing in high-voltage applications. This constant on-time (COT) converter is ideal for low-noise, high-current, and fast load transient requirements, operating with adaptive on-time switching pulse. Over the input voltage range, input voltage feedforward is used to achieve a quasi-fixed switching frequency. A controllable on time as low as 50 ns permits high step-down ratios and a minimum forced off time of 50 ns provides extremely high duty cycles, allowing VIN to drop close to VOUT before frequency foldback occurs. At light loads, the device transitions into an ultra-low IQ mode to maintain high efficiency and prevent draining battery cells connected to the input when the system is in standby. The LM5012 implements a smart peak current limit detection circuit to ensure robust protection during output short circuit conditions. Control loop compensation is not required for this regulator, reducing design time and external component count.

The LM5012 incorporates additional features for comprehensive system requirements:

  • Power-rail sequencing and fault reporting
  • Internally-fixed soft start
  • Open-drain power good
  • Monotonic start-up into prebiased loads
  • Precision enable for programmable line undervoltage lockout (UVLO)
  • Smart cycle-by-cycle current limit for optimal inductor sizing
  • Thermal shutdown with automatic recovery

These features enable a flexible and easy-to-use platform for a wide range of applications. The LM5012 supports a wide range of end-equipment systems requiring a regulated output from a high input supply where the transient voltage deviates from the DC level. The following are examples of such end equipment systems:

  • High cell-count battery-pack systems
  • 24-V industrial systems
  • 48-V telecommunication and PoE voltage ranges

The pin arrangement is designed for a simple layout requiring only a few external components.