SNVS616H April   2009  – July 2015 LM3429 , LM3429-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
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 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  Current Regulators
      2. 7.3.2  Predictive Off-Time (PRO) Control
      3. 7.3.3  Switching Frequency
      4. 7.3.4  Average LED Current
      5. 7.3.5  Analog Dimming
      6. 7.3.6  Current Sense and Current Limit
      7. 7.3.7  Control Loop Compensation
      8. 7.3.8  Output Overvoltage Lockout (OVLO)
      9. 7.3.9  Input Undervoltage Lockout (UVLO)
      10. 7.3.10 PWM Dimming
      11. 7.3.11 Startup Regulator (VCC LDO)
      12. 7.3.12 Thermal Shutdown
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Inductor
      2. 8.1.2 LED Dynamic Resistance (rD)
      3. 8.1.3 Output Capacitor
      4. 8.1.4 Input Capacitors
      5. 8.1.5 N-Channel MosFET (NFET)
      6. 8.1.6 Re-Circulating Diode
    2. 8.2 Typical Applications
      1. 8.2.1 Basic Topology Schematics
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Operating Point
          2. 8.2.1.2.2  Switching Frequency
          3. 8.2.1.2.3  Average LED Current
          4. 8.2.1.2.4  Inductor Ripple Current
          5. 8.2.1.2.5  LED Ripple Current
          6. 8.2.1.2.6  Peak Current Limit
          7. 8.2.1.2.7  Loop Compensation
          8. 8.2.1.2.8  Input Capacitance
          9. 8.2.1.2.9  NFET
          10. 8.2.1.2.10 Diode
          11. 8.2.1.2.11 Output OVLO
          12. 8.2.1.2.12 Input UVLO
          13. 8.2.1.2.13 PWM Dimming Method
          14. 8.2.1.2.14 Analog Dimming Method
      2. 8.2.2 Buck-Boost Application - 6 LEDs at 1 A
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1  Operating Point
          2. 8.2.2.2.2  Switching Frequency
          3. 8.2.2.2.3  Average LED Current
          4. 8.2.2.2.4  Inductor Ripple Current
          5. 8.2.2.2.5  Output Capacitance
          6. 8.2.2.2.6  Peak Current Limit
          7. 8.2.2.2.7  Loop Compensation
          8. 8.2.2.2.8  Input Capacitance
          9. 8.2.2.2.9  NFET
          10. 8.2.2.2.10 Diode
          11. 8.2.2.2.11 Input UVLO
          12. 8.2.2.2.12 Output OVLO
        3. 8.2.2.3 Application Curve
      3. 8.2.3 Boost PWM Dimming Application - 9 LEDs at 1 A
        1. 8.2.3.1 Detailed Design Procedure
      4. 8.2.4 Buck-Boost Analog Dimming Application - 4 LEDs at 2A
        1. 8.2.4.1 Detailed Design Procedure
      5. 8.2.5 Boost Analog Dimming Application - 12 LEDs at 700 mA
        1. 8.2.5.1 Detailed Design Procedure
      6. 8.2.6 Buck-Boost PWM Dimming Application - 6 LEDs at 500 mA
        1. 8.2.6.1 Detailed Design Procedure
      7. 8.2.7 Buck Application - 3 LEDS at 1.25 A
        1. 8.2.7.1 Detailed Design Procedure
      8. 8.2.8 Buck-Boost Thermal Foldback Application - 8 LEDs at 2.5 A
        1. 8.2.8.1 Detailed Design Procedure
      9. 8.2.9 SEPIC Application - 5 LEDs at 750 mA
        1. 8.2.9.1 Detailed Design Procedure
  9. 9 Power Supply Recommendations
    1. 9.1 Input Supply Current Limit
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 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

The device is designed to operate from an input voltage supply range from 4.5 V to 75 V. This input supply should be well regulated. If the input supply is located more than a few inches from the EVM or PCB, additional bulk capacitance may be required in addition to the ceramic bypass capacitors.

9.1 Input Supply Current Limit

It is important to set the output current limit of your input supply to an appropriate value to avoid delays in your converter analysis and optimization. If not set high enough, current limit can be tripped during start-up or when your converter output power is increased, causing a foldback or shut-down condition. It is a common oversight when powering up a converter for the first time.