SNVS077J May   2004  – June 2016 LM2677

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 - 3.3 V
    6. 6.6  Electrical Characteristics - 5 V
    7. 6.7  Electrical Characteristics - 12 V
    8. 6.8  Electrical Characteristics - Adjustable
    9. 6.9  Electrical Characteristics - All Output Voltage Versions
    10. 6.10 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 Switch Output
      2. 7.3.2 CBoost
      3. 7.3.3 Ground
      4. 7.3.4 Sync
      5. 7.3.5 Feedback
      6. 7.3.6 ON/OFF
      7. 7.3.7 DAP (VSON Package)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Inductor
      2. 8.1.2 Output Capacitor
      3. 8.1.3 Input and Output Capacitor Codes
      4. 8.1.4 Input Capacitor
      5. 8.1.5 Catch Diode
      6. 8.1.6 Boost Capacitor
      7. 8.1.7 SYNC Components
      8. 8.1.8 Additional Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Fixed Output Voltage Applications
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Adjustable Output Voltage Applications
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 VSON Package Devices
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    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)

10 Layout

10.1 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 16 and Figure 20) 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 C 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 place both resistors near the IC, and route the wiring away from the inductor, especially an open-core type of inductor.

10.1.1 VSON Package Devices

The LM2677 is offered in the 14-pin VSON surface mount package to allow for a significantly decreased footprint with equivalent power dissipation compared to the TO-220 or TO-263. For details on mounting and soldering specifications, see application note, AN-1187 Leadless Leadframe Package (LLP).

10.2 Layout Example

LM2677 layout_example_snvs077.gif Figure 22. LM2677 Sample Layout