SNVS676I August   2010  – April  2018 LM5119

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application Circuit
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Switching Characteristics
    7. 6.7 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  High Voltage Start-Up Regulator
      2. 7.3.2  UVLO
      3. 7.3.3  Enable 2
      4. 7.3.4  Oscillator and Sync Capability
      5. 7.3.5  Error Amplifiers and PWM Comparators
      6. 7.3.6  Ramp Generator
      7. 7.3.7  Current Limit
      8. 7.3.8  Hiccup Mode Current Limiting
      9. 7.3.9  Soft Start
      10. 7.3.10 HO and LO Output Drivers
      11. 7.3.11 Maximum Duty Cycle
      12. 7.3.12 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Diode Emulation
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Miscellaneous Functions
      2. 8.1.2 Interleaved Two-Phase Operation
      3. 8.1.3 Interleaved 4-Phase Operation
    2. 8.2 Typical Applications
      1. 8.2.1 Dual-output Design Example
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Timing Resistor
          2. 8.2.1.2.2  Output Inductor
          3. 8.2.1.2.3  Current Sense Resistor
          4. 8.2.1.2.4  Ramp Resistor and Ramp Capacitor
          5. 8.2.1.2.5  Output Capacitors
          6. 8.2.1.2.6  Input Capacitors
          7. 8.2.1.2.7  VCC Capacitor
          8. 8.2.1.2.8  Bootstrap Capacitor
          9. 8.2.1.2.9  Soft-Start Capacitor
          10. 8.2.1.2.10 Restart Capacitor
          11. 8.2.1.2.11 Output Voltage Divider
          12. 8.2.1.2.12 UVLO Divider
            1. 8.2.1.2.12.1 MOSFET Selection
          13. 8.2.1.2.13 MOSFET Snubber
          14. 8.2.1.2.14 Error Amplifier Compensation
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Two-Phase Design Example
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Switching Jitter Root Causes and Solutions
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.1 Overview

The LM5119 high voltage switching regulator features all of the functions necessary to implement an efficient dual channel buck regulator that operates over a very wide input voltage range. The LM5119 may be configured as two independent regulators or as a single high current regulator with two interleaved channels. This easy-to-use regulator integrates high-side and low-side MOSFET drivers capable of supplying peak currents of 2.5 A (VCC = 8 V). The regulator control method is based on current mode control using an emulated current ramp. Emulated peak current mode control provides inherent line feedforward, cycle-by-cycle current limiting and ease-of-loop compensation. The use of an emulated control ramp reduces noise sensitivity of the pulse-width modulation circuit, allowing reliable processing of the very small duty cycles necessary in high input voltage applications. The switching frequency is user programmable from 50 kHz to 750 kHz. An oscillator or synchronization pin allows the operating frequency to be set by a single resistor or synchronized to an external clock. An undervoltage lockout and channel2 enable pin allows either both regulators to be disabled or channel2 to be disabled with full operation of channel1. Fault protection features include current limiting, thermal shutdown, and remote shutdown capability. The undervoltage lockout input enables both channels when the input voltage reaches a user selected threshold and provides a very low quiescent shutdown current when pulled low. The 32-pin WQFN package features an exposed pad to aid in thermal dissipation.