SNVS963C SEPTEMBER   2013  – June 2016 LM5121 , LM5121-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings: LM5121
    3. 6.3 ESD Ratings: LM5121-Q1
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Thermal Information
    6. 6.6 Electrical 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  Undervoltage Lockout (UVLO)
      2. 7.3.2  High Voltage VCC Regulator
      3. 7.3.3  Oscillator
      4. 7.3.4  Slope Compensation
      5. 7.3.5  Error Amplifier
      6. 7.3.6  PWM Comparator
      7. 7.3.7  Disconnection Switch Control
      8. 7.3.8  Soft-Start
      9. 7.3.9  HO and LO Drivers
      10. 7.3.10 Bypass Operation (VOUT = VIN)
      11. 7.3.11 Cycle-by-Cycle Current Limit
      12. 7.3.12 Circuit Breaker Function
      13. 7.3.13 Clock Synchronization
      14. 7.3.14 Maximum Duty Cycle
      15. 7.3.15 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Hiccup Mode Short Circuit and Overload Protection
      2. 7.4.2 MODE Control (Forced PWM Mode and Diode Emulation Mode)
      3. 7.4.3 MODE Control (Skip Cycle Mode and Pulse Skipping Mode)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Feedback Compensation
      2. 8.1.2 Sub-Harmonic Oscillation
      3. 8.1.3 Output Overvoltage Protection
      4. 8.1.4 Input Transient Suppression
      5. 8.1.5 Inrush Current Limit Programming
      6. 8.1.6 Reverse Battery Protection + Disconnect Switch Control
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Timing Resistor RT
        2. 8.2.2.2  UVLO Divider RUV2, RUV1
        3. 8.2.2.3  Input Inductor LIN
        4. 8.2.2.4  Current Sense Resistor RS
        5. 8.2.2.5  Current Sense Filter RCSFP, RCSFN, CCS
        6. 8.2.2.6  Slope Compensation Resistor RSLOPE
        7. 8.2.2.7  Output Capacitor COUT
        8. 8.2.2.8  Input Capacitor CIN
        9. 8.2.2.9  VIN Filter RVIN, CVIN
        10. 8.2.2.10 Bootstrap Capacitor CBST and Boost Diode DBST
        11. 8.2.2.11 VCC Capacitor CVCC
        12. 8.2.2.12 Output Voltage Divider RFB1, RFB2
        13. 8.2.2.13 Soft-Start Capacitor CSS
        14. 8.2.2.14 Restart Capacitor CRES
        15. 8.2.2.15 Low-Side Power Switch QL
        16. 8.2.2.16 High-Side Power Switch QH and Additional Parallel Schottky Diode
        17. 8.2.2.17 Snubber Components
        18. 8.2.2.18 Disconnect Switch QD Selection
        19. 8.2.2.19 Freewheeling Diode DF Selection
        20. 8.2.2.20 Loop Compensation Components CCOMP, RCOMP, CHF
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

9 Power Supply Recommendations

LM5121 is a power management device. The power supply for the device is any DC voltage source within the specified input range.