SNVSAN3F August   2017  – November 2020 LMR33630

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  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
    6. 7.6 Timing Characteristics
    7. 7.7 System Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Power-Good Flag Output
      2. 8.3.2 Enable and Start-up
      3. 8.3.3 Current Limit and Short Circuit
      4. 8.3.4 Undervoltage Lockout and Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Auto Mode
      2. 8.4.2 Dropout
      3. 8.4.3 Minimum Switch On-Time
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1  Custom Design With WEBENCH® Tools
        2. 9.2.2.2  Choosing the Switching Frequency
        3. 9.2.2.3  Setting the Output Voltage
        4. 9.2.2.4  Inductor Selection
        5. 9.2.2.5  Output Capacitor Selection
        6. 9.2.2.6  Input Capacitor Selection
        7. 9.2.2.7  CBOOT
        8. 9.2.2.8  VCC
        9. 9.2.2.9  CFF Selection
        10. 9.2.2.10 External UVLO
        11. 9.2.2.11 Maximum Ambient Temperature
      3. 9.2.3 Application Curves
    3. 9.3 What to Do and What Not to Do
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Ground and Thermal Considerations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary

9.2.1 Design Requirements

Table 9-1 provides the parameters for our detailed design procedure example:

Table 9-1 Detailed Design Parameters
DESIGN PARAMETER EXAMPLE VALUE
Input voltage 12 V (6 V to 36 V)
Output voltage 5 V
Maximum output current 0 A to 3 A
Switching frequency 400 kHz
Table 9-2 Typical External Component Values
ƒSW (kHz) VOUT (V) L (µH) COUT (RATED CAPACITANCE) RFBT (Ω) RFBB (Ω) CIN + CHF CBOOT CVCC CFF
400 3.3 6.8 4 × 22 µF 100 k 43.2 k 10 µF + 220 nF 100 nF 1 µF open
1400 3.3 2.2 2 × 22 µF 100 k 43.2 k 10 µF + 220 nF 100 nF 1 µF open
2100 3.3 1.2 2 × 22 µF 100 k 43.2 k 10 µF + 220 nF 100 nF 1 µF open
400 5 8 4 × 22 µF 100 k 24.9 k 10 µF + 220 nF 100 nF 1 µF open
1400 5 2.2 2 × 22 µF 100 k 24.9 k 10 µF + 220 nF 100 nF 1 µF open
2100 5 1.5 2 × 22 µF 100 k 24.9 k 10 µF + 220 nF 100 nF 1 µF open
400 12 15 4 × 22 µF 100 k 9.09 k 10 µF + 220 nF 100 nF 1 µF open
1400 12 4.7 4 × 10 µF 100 k 9.09 k 10 µF + 220 nF 100 nF 1 µF open
2100 12 3.3 4 × 10 µF 100 k 9.09 k 10 µF + 220 nF 100 nF 1 µF open