SNVSAU4C September   2018  – April 2024 LM5164

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Control Architecture
      2. 6.3.2  Internal VCC Regulator and Bootstrap Capacitor
      3. 6.3.3  Regulation Comparator
      4. 6.3.4  Internal Soft Start
      5. 6.3.5  On-Time Generator
      6. 6.3.6  Current Limit
      7. 6.3.7  N-Channel Buck Switch and Driver
      8. 6.3.8  Synchronous Rectifier
      9. 6.3.9  Enable/Undervoltage Lockout (EN/UVLO)
      10. 6.3.10 Power Good (PGOOD)
      11. 6.3.11 Thermal Protection
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
      2. 6.4.2 Active Mode
      3. 6.4.3 Sleep Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Custom Design With WEBENCH® Tools
        2. 7.2.2.2 Switching Frequency (RRON)
        3. 7.2.2.3 Buck Inductor (LO)
        4. 7.2.2.4 Output Capacitor (COUT)
        5. 7.2.2.5 Input Capacitor (CIN)
        6. 7.2.2.6 Type-3 Ripple Network
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 Compact PCB Layout for EMI Reduction
        2. 7.4.1.2 Feedback Resistors
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Third-Party Products Disclaimer
      2. 8.1.2 Development Support
        1. 8.1.2.1 Custom Design With WEBENCH® Tools
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.1 Overview

The LM5164 is an easy-to-use, ultra-low IQ constant on-time (COT) synchronous step-down buck regulator. With integrated high-side and low-side power MOSFETs, the LM5164 is a low-cost, highly efficient buck converter that operates from a wide input voltage of 6 V to 100 V, delivering up to 1-A DC load current. The LM5164 is available in an 8-pin SO PowerPAD 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 a predictive on-time switching pulse. Over the input voltage range, input voltage feedforward is employed 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 LM5164 implements a smart peak and valley 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 LM5164 incorporates additional features for comprehensive system requirements, including an open-drain power good circuit for the following:

  • Power-rail sequencing and fault reporting
  • Internally-fixed soft start
  • 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 LM5164 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:

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

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