SNVSB73 September   2018 LM2735-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Boost Application Circuit
      2.      Efficiency vs Load Current VO = 12 V
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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
      1. 7.1.1 Theory of Operation
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Current Limit
      2. 7.3.2 Thermal Shutdown
      3. 7.3.3 Soft Start
      4. 7.3.4 Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable Pin and Shutdown Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1  LM2735X-Q1 SOT-23 Design Example 1
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 8.2.1.2.2 Inductor Selection
          3. 8.2.1.2.3 Input Capacitor
          4. 8.2.1.2.4 Output Capacitor
          5. 8.2.1.2.5 Setting the Output Voltage
        3. 8.2.1.3 Application Curves
      2. 8.2.2  LM2735Y-Q1 SOT-23 Design Example 2
      3. 8.2.3  LM2735X-Q1 WSON Design Example 3
      4. 8.2.4  LM2735Y-Q1 WSON Design Example 4
      5. 8.2.5  LM2735X-Q1 SOT-23 Design Example 6
      6. 8.2.6  LM2735Y-Q1 SOT-23 Design Example 7
      7. 8.2.7  LM2735X-Q1 SOT-23 Design Example 8
      8. 8.2.8  LM2735Y-Q1 SOT-23 Design Example 9
      9. 8.2.9  LM2735X-Q1 WSON Design Example 10
      10. 8.2.10 LM2735Y-Q1 WSON Design Example 11
      11. 8.2.11 LM2735X-Q1 WSON SEPIC Design Example 12
      12. 8.2.12 LM2735X-Q1 SOT-23 LED Design Example 14
      13. 8.2.13 LM2735Y-Q1 WSON FlyBack Design Example 15
      14. 8.2.14 LM2735X-Q1 SOT-23 LED Design Example 16 VRAIL > 5.5 V Application
      15. 8.2.15 LM2735X-Q1 SOT-23 LED Design Example 17 Two-Input Voltage Rail Application
      16. 8.2.16 SEPIC Converter
        1. 8.2.16.1 Detailed Design Procedure
          1. 8.2.16.1.1 SEPIC Design Guide
          2. 8.2.16.1.2 Small Ripple Approximation
          3. 8.2.16.1.3 Steady State Analysis With Loss Elements
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 WSON Package
    2. 10.2 Layout Examples
    3. 10.3 Thermal Considerations
      1. 10.3.1 Definitions
      2. 10.3.2 PCB Design With Thermal Performance in Mind
      3. 10.3.3 LM2735-Q1 Thermal Models
      4. 10.3.4 Calculating Efficiency, and Junction Temperature
        1. 10.3.4.1 Example Efficiency Calculation
      5. 10.3.5 Calculating RθJA and RΨJC
        1. 10.3.5.1 Procedure
        2. 10.3.5.2 Example From Previous Calculations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Custom Design With WEBENCH® Tools
    3. 11.3 Documentation Support
      1. 11.3.1 Related Documentation
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.1.2.5 Setting the Output Voltage

The output voltage is set using the following equation where R1 is connected between the FB pin and GND, and R2 is connected between VOUT and the FB pin.

LM2735-Q1 20215829.gifFigure 20. Setting VOUT

A good value for R1 is 10 kΩ.

Equation 16. LM2735-Q1 20215830.gif