SNVS450F September   2006  – October 2015 LM3402 , LM3402HV

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 Timing Requirements
    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 Controlled ON-time Overview
      2. 7.3.2 Average LED Current Accuracy
      3. 7.3.3 Maximum Output Voltage
      4. 7.3.4 Minimum Output Voltage
      5. 7.3.5 High Voltage Bias Regulator
      6. 7.3.6 Internal MOSFET and Driver
      7. 7.3.7 Fast Shutdown for PWM Dimming
      8. 7.3.8 Peak Current Limit
      9. 7.3.9 Overvoltage and Overcurrent Comparator
    4. 7.4 Device Functional Modes
      1. 7.4.1 Low Power Shutdown
      2. 7.4.2 Thermal Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Switching Frequency
      2. 8.1.2 LED Ripple Current
      3. 8.1.3 Buck Converters Without Output Capacitors
      4. 8.1.4 Buck Converters With Output Capacitors
      5. 8.1.5 Input Capacitors
      6. 8.1.6 Recirculating Diode
      7. 8.1.7 LED Current During DIM Mode
      8. 8.1.8 Transient Protection Considerations
        1. 8.1.8.1 CS Pin Protection
        2. 8.1.8.2 CS Pin Protection With OVP
        3. 8.1.8.3 VIN Pin Protection
        4. 8.1.8.4 General Comments Regarding Other Pins
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 RON and tON
        2. 8.2.2.2 Using an Output Capacitor
        3. 8.2.2.3 Output Inductor
          1. 8.2.2.3.1 RSNS
        4. 8.2.2.4 Input Capacitor
        5. 8.2.2.5 Recirculating Diode
          1. 8.2.2.5.1 CB and CF
        6. 8.2.2.6 Efficiency
        7. 8.2.2.7 Die Temperature
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout
      2. 10.1.2 Ground Plane and Shape Routing
      3. 10.1.3 Current Sensing
      4. 10.1.4 Remote LED Arrays
    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 Related Links
    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

5 Pin Configuration and Functions

DGK Package
8-Pin VSSOP
Top View
LM3402 LM3402HV 20192102.gif
DDA Package
8-Pin HSOP
Top View
LM3402 LM3402HV 20192145.gif

Pin Functions

PIN I/O DESCRIPTION
NO. NAME
1 SW O Switch pin. Connect this pin to the output inductor and Schottky diode.
2 BOOT O MOSFET drive bootstrap pin. Connect a 10-nF ceramic capacitor from this pin to SW.
3 DIM I Input for PWM dimming. Connect a logic-level PWM signal to this pin to enable and disable the power MOSFET and reduce the average light output of the LED array.
4 GND — Ground pin. Connect this pin to system ground.
5 CS I Current sense feedback pin. Set the current through the LED array by connecting a resistor from this pin to ground.
6 RON I ON-time control pin. A resistor connected from this pin to VIN sets the regulator controlled ON-time.
7 VCC O Output of the internal 7-V linear regulator. Bypass this pin to ground with a minimum 0.1-µF ceramic capacitor with X5R or X7R dielectric.
8 VIN I Input voltage pin. Nominal operating input range for this pin is 6 V to 42 V (LM3402) or 6 V to 75 V (LM3402HV).
DAP — Thermal Pad. Connect to ground. Place 4-6 vias from DAP to bottom layer ground plane.