SLVS641B April   2008  – March  2015 TL4242

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 PWM Input
      2. 7.3.2 ST Output
        1. 7.3.2.1 Function and Timing Diagram
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Input Supply Voltage
      2. 8.1.2 Power Dissipation in TL4242
      3. 8.1.3 Setting the Output Current
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Voltage
        2. 8.2.2.2 Shunt Resistor
      3. 8.2.3 Application Curve
  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 Trademarks
    2. 11.2 Electrostatic Discharge Caution
    3. 11.3 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

10 Layout

10.1 Layout Guidelines

The REF pin should be routed directly to the shunt resistor, RREF. If there is a long PCB trace between the LED string and the shunt resistor, the REF pin should connect close to the shunt resistor (rather than close to the LED string) to allow for accurate sensing across the shunt resistor.

The traces for I and Q will carry the full LED current. These traces should be the appropriate width to carry the LED current.

The exposed thermal pad on the bottom of the TL4242 should be connected to the PCB. The thermal pad helps to dissipate heat in the case of high power dissipation in the device. To further enhance the thermal performance of the device, the thermal pad can be connected by vias to the ground layer in the PCB.

10.2 Layout Example

TL4242 TL4242_layout.gifFigure 8. PCB Layout