SLUSF64B August   2024  – January 2025 LMR51625 , LMR51635

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Fixed Frequency Peak Current Mode Control
      2. 7.3.2 Adjustable Output Voltage
      3. 7.3.3 Enable
      4. 7.3.4 Minimum ON Time, Minimum OFF Time, and Frequency Foldback
      5. 7.3.5 Bootstrap Voltage
      6. 7.3.6 Overcurrent and Short-Circuit Protection
      7. 7.3.7 Soft Start
      8. 7.3.8 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
      3. 7.4.3 CCM Mode
      4. 7.4.4 Light Load Operation (PFM Version)
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Output Voltage Set-Point
        3. 8.2.2.3 Switching Frequency
        4. 8.2.2.4 Inductor Selection
        5. 8.2.2.5 Output Capacitor Selection
        6. 8.2.2.6 Input Capacitor Selection
        7. 8.2.2.7 Bootstrap Capacitor
        8. 8.2.2.8 Undervoltage Lockout Set-Point
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Compact Layout for EMI Reduction
        2. 8.4.1.2 Feedback Resistors
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 Development Support
        1. 9.1.2.1 Custom Design With WEBENCH® Tools
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.2 Typical Application

The LMR51635 only requires a few external components to convert from a wide voltage range supply to a fixed output voltage. Figure 8-1 shows a basic schematic.

LMR51625 LMR51635 Application CircuitFigure 8-1 Application Circuit

The external components must fulfill the needs of the application and the stability criteria of the control loop of the device. Table 8-1 and Table 8-2 can be used to simplify the output filter component selection.

Table 8-1 Typical External Component Values for LMR51625, 2.5A Output Current
fSW (kHz)VOUT (V)L (µH)COUT (1)RFBT (kΩ)RFBB (kΩ)

CFF

400

3.3

10

2 × 33uF / 10V

31.6

10.2

Open

5

15

2 × 22uF / 16V

53.6

10.2

Open

12

22

22uF / 35V

143

10.2

Open

11003.33.333uF / 10V

31.6

10.2

Open

54.722uF / 16V

53.6

10.2

Open

(1) Ceramic capacitor is used in this table. All the COUT values are after derating.
Table 8-2 Typical External Component Values for LMR51635, 3.5A Output Current
fSW (kHz)VOUT (V)L (µH)COUT (1)RFBT (kΩ)RFBB (kΩ)CFF
4003.35.62 × 47uF / 10V31.610.2

Open

5102 × 33uF / 16V53.610.2Open
121510uF + 22uF / 35V14310.2Open
1100

3.3

2.2

2 × 22uF / 10V

31.6

10.2Open

5

3.3

33uF / 16V

53.6

10.2Open
(1) Ceramic capacitor is used in this table. All the COUT values are after derating.