SNVS129G May   2004  – June 2025 LM2675

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
      1. 5.4.1 Electrical Characteristics – 3.3 V
    5. 5.5  Electrical Characteristics – 5 V
    6. 5.6  Electrical Characteristics – 12 V
    7. 5.7  Electrical Characteristics – Adjustable
    8. 5.8  Electrical Characteristics – All Output Voltage Versions
    9. 5.9  Typical Characteristics
    10. 5.10 Typical Characteristics – Fixed Output Voltage Versions
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Adjustable Output Voltage
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
      2. 6.4.2 Active Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Fixed Output Voltage Application
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 Custom Design with WEBENCH® Tools
          2. 7.2.1.2.2 Inductor Selection (L1)
          3. 7.2.1.2.3 Output Capacitor Selection (COUT)
          4. 7.2.1.2.4 Catch Diode Selection (D1)
          5. 7.2.1.2.5 Input Capacitor (CIN)
          6. 7.2.1.2.6 Boost Capacitor (CB)
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Adjustable Output Voltage Application
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
          1. 7.2.2.2.1 Programming Output Voltage
          2. 7.2.2.2.2 Inductor Selection (L1)
          3. 7.2.2.2.3 Output Capacitor SeIection (COUT)
          4. 7.2.2.2.4 Catch Diode Selection (D1)
          5. 7.2.2.2.5 Input Capacitor (CIN)
          6. 7.2.2.2.6 Boost Capacitor (CB)
        3. 7.2.2.3 Application Curve
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 WSON Package Devices
      2. 7.4.2 Layout Examples
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 Custom Design with WEBENCH® Tools
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
7.2.2.2.4 Catch Diode Selection (D1)

In normal operation, the average current of the catch diode is the load current times the catch diode duty cycle, 1-D (D is the switch duty cycle, which is approximately VOUT/VIN). The largest value of the catch diode average current occurs at the maximum input voltage (minimum D). For normal operation, the catch diode current rating must be at least 1.3 times greater than the maximum average current. However, if the power supply design must withstand a continuous output short, the diode must have a current rating greater than the maximum current limit of the LM2675. The most stressful condition for this diode is a shorted output condition (see Table 7-4). Schottky diodes provide the best performance, and in this example a 1-A, 40-V Schottky diode can be a good choice. If the circuit must withstand a continuous shorted output, TI recommends a Schottky diode of higher current (at least 2.2 A).

The reverse voltage rating of the diode must be at least 1.25 times the maximum input voltage. Because of the fast switching speed and low forward voltage drop, Schottky diodes provide the best performance and efficiency. The Schottky diode must be placed close to the LM2675 using short leads and short printed circuit traces.