SNVS602L March   2009  – June 2016 LM3409 , LM3409-Q1 , LM3409HV , LM3409HV-Q1

PRODUCTION DATA.  

1. 1 Features
2. 2 Applications
3. 3 Description
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
   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 Buck Current Regulators
      2. 8.3.2 Controlled Off-Time (COFT) Architecture
         1. 8.3.2.1 Adjustable Peak Current Control
         2. 8.3.2.2 Controlled Off-Time
      3. 8.3.3 Average LED Current
      4. 8.3.4 Inductor Current Ripple
      5. 8.3.5 Switching Frequency
      6. 8.3.6 PWM Dimming Using the EN Pin
      7. 8.3.7 High Voltage Negative BIAS Regulator
      8. 8.3.8 External Parallel FET PWM Dimming
   4. 8.4 Device Functional Modes
      1. 8.4.1 Low-Power Shutdown
      2. 8.4.2 Thermal Shutdown
9. 9 Application and Implementation
   1. 9.1 Application Information
      1. 9.1.1 Input Undervoltage Lockout (UVLO)
      2. 9.1.2 Operation Near Dropout
      3. 9.1.3 LED Ripple Current
      4. 9.1.4 Buck Converters without Output Capacitors
      5. 9.1.5 Buck Converters With Output Capacitors
      6. 9.1.6 Output Overvoltage Protection
      7. 9.1.7 Input Capacitors
      8. 9.1.8 P-Channel MOSFET (PFET)
      9. 9.1.9 Re-Circulating Diode
   2. 9.2 Typical Applications
      1. 9.2.1 EN PIN PWM Dimming Application for 10 LEDs
         1. 9.2.1.1 Design Requirements
         2. 9.2.1.2 Detailed Design Procedure
            1. 9.2.1.2.1  Nominal Switching Frequency
            2. 9.2.1.2.2  Inductor Ripple Current
            3. 9.2.1.2.3  Average LED Current
            4. 9.2.1.2.4  Output Capacitance
            5. 9.2.1.2.5  Input Capacitance
            6. 9.2.1.2.6  PFET
            7. 9.2.1.2.7  Diode
            8. 9.2.1.2.8  Input UVLO
            9. 9.2.1.2.9  IADJ Connection Method
            10. 9.2.1.2.10 PWM Dimming Method
         3. 9.2.1.3 Application Curve
      2. 9.2.2 Analog Dimming Application for 4 LEDs
         1. 9.2.2.1 Design Requirements
         2. 9.2.2.2 Detailed Design Procedure
            1. 9.2.2.2.1  Nominal Switching Frequency
            2. 9.2.2.2.2  Inductor Ripple Current
            3. 9.2.2.2.3  Average LED Current
            4. 9.2.2.2.4  Output Capacitance
            5. 9.2.2.2.5  Input Capacitance
            6. 9.2.2.2.6  PFET
            7. 9.2.2.2.7  Diode
            8. 9.2.2.2.8  Input UVLO
            9. 9.2.2.2.9  IADJ Connection Method
            10. 9.2.2.2.10 PWM Dimming Method
         3. 9.2.2.3 Application Curve
      3. 9.2.3 LM3409 Buck Converter Application
         1. 9.2.3.1 Design Requirements
         2. 9.2.3.2 Detailed Design Procedure
            1. 9.2.3.2.1  Nominal Switching Frequency
            2. 9.2.3.2.2  Inductor Ripple Current
            3. 9.2.3.2.3  Average LED Current
            4. 9.2.3.2.4  Output Capacitance
            5. 9.2.3.2.5  Input Capacitance
            6. 9.2.3.2.6  PFET
            7. 9.2.3.2.7  Diode
            8. 9.2.3.2.8  Input UVLO
            9. 9.2.3.2.9  IADJ Connection Method
            10. 9.2.3.2.10 PWM Dimming Method
10. 10Power Supply Recommendations
11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
12. 12Device and Documentation Support
    1. 12.1 Device Support
       1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Related Links
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
13. 13Mechanical, Packaging, and Orderable Information