SNVS416C November   2005  – February 2016 LM27951

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 Charge Pump
      2. 7.3.2 Soft Start
      3. 7.3.3 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable and PWM Pins
      2. 7.4.2 Adjusting LED Brightness (PWM Control)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Maximum Output Current, Maximum LED Voltage, Minimum Input Voltage
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Setting LED Currents
        2. 8.2.2.2 Capacitor Selection
        3. 8.2.2.3 Parallel Dx Outputs for Increased Current Drive
        4. 8.2.2.4 Power Efficiency
        5. 8.2.2.5 Power Dissipation
      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 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    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

10 Layout

10.1 Layout Guidelines

The WSON is a leadframe-based chip scale package (CSP) with very good thermal properties. This package has an exposed DAP (die attach pad) thermal pad at the center of the package measuring 3 mm × 1.6 mm. The main advantage of this exposed DAP is to offer lower thermal resistance when it is soldered to the thermal land on the PCB. For PCB layout, TI highly recommends a 1:1 ratio between the package and the PCB thermal land. To further enhance thermal conductivity, the PCB thermal land may include vias to a ground plane. For more detailed instructions on mounting WSON packages, refer to AN-1187 Leadless Leadframe Package (LLP) SNOA401.

10.2 Layout Example

LM27951 layout_snvs416.gif Figure 8. LM27951 Layout Example