SNVS129F May   2004  – June 2016 LM2675

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics - 3.3 V
    6. 7.6  Electrical Characteristics - 5 V
    7. 7.7  Electrical Characteristics - 12 V
    8. 7.8  Electrical Characteristics - Adjustable
    9. 7.9  Electrical Characteristics - All Output Voltage Versions
    10. 7.10 Typical Characteristics
    11. 7.11 Typical Characteristics - Fixed Output Voltage Versions
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Adjustable Output Voltage
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Fixed Output Voltage Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Inductor Selection (L1)
          2. 9.2.1.2.2 Output Capacitor Selection (COUT)
          3. 9.2.1.2.3 Catch Diode Selection (D1)
          4. 9.2.1.2.4 Input Capacitor (CIN)
          5. 9.2.1.2.5 Boost Capacitor (CB)
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Adjustable Output Voltage Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Programming Output Voltage
          2. 9.2.2.2.2 Inductor Selection (L1)
          3. 9.2.2.2.3 Output Capacitor SeIection (COUT)
          4. 9.2.2.2.4 Catch Diode Selection (D1)
          5. 9.2.2.2.5 Input Capacitor (CIN)
          6. 9.2.2.2.6 Boost Capacitor (CB)
        3. 9.2.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 WSON Package Devices
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

11 Layout

11.1 Layout Guidelines

Layout is very important in switching regulator designs. Rapidly switching currents associated with wiring inductance can generate voltage transients which can cause problems. For minimal inductance and ground loops, the wires indicated by heavy lines (in Figure 19 and Figure 24) must be wide printed circuit traces and must be kept as short as possible. For best results, external components must be placed as close to the switcher IC as possible using ground plane construction or single-point grounding.

If open-core inductors are used, take special care as to the location and positioning of this type of inductor. Allowing the inductor flux to intersect sensitive feedback, IC ground path, and COUT wiring can cause problems.

When using the adjustable version, take special care as to the location of the feedback resistors and the associated wiring. Physically locate both resistors near the IC, and route the wiring away from the inductor, especially an open-core type of inductor.

11.1.1 WSON Package Devices

The LM2675 is offered in the 16-pin WSON surface-mount package to allow for increased power dissipation compared to the SOIC and PDIP.

The die attach pad (DAP) can and must be connected to PCB Ground plane or island. For CAD and assembly guidelines see AN-1187 Leadless Leadframe Package (LLP).

11.2 Layout Examples

LM2675 1280336.png
CIN = 15-μF, 50-V, Solid Tantalum Sprague 594D series
COUT = 68-μF, 16-V, Solid Tantalum Sprague 594D series
D1 = 1-A, 40-V Schottky Rectifier, surface mount
L1 = 33-μH, L23, Coilcraft DO3316
CB = 0.01-μF, 50-V ceramic
Figure 26. Typical Surface Mount PC Board Layout, Fixed Output
LM2675 1280337.png
CIN = 15-μF, 50-V, Solid Tantalum Sprague 594D series
COUT = 33-μF, 25-V, Solid Tantalum Sprague 594D series
D1 = 1-A, 40-V Schottky Rectifier, surface mount
L1 = 68-μH, L30, Coilcraft DO3316
CB = 0.01-μF, 50-V ceramic
R1 = 1k, 1%
R2 = Use formula in Detailed Design Procedure
Figure 27. Typical Surface Mount PC Board Layout, Adjustable Output