SNVSBQ5 June   2021 LMR33620AP-Q1 , LMR33630AP-Q1

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. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Ground and Thermal Considerations
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. 12.1.2.1 Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Support Resources
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.2 Enable and Start-Up

Start-up and shutdown are controlled by the EN input. This input features precision thresholds, allowing the use of an external voltage divider to provide an adjustable input UVLO (see Section 9.2.2.10). Applying a voltage of ≥ VEN-VCC_H causes the device to enter Standby mode, powering the internal VCC, but not producing an output voltage. Increasing the EN voltage to VEN-H fully enables the device, allowing it to enter Start-up mode and start the soft-start period. When the EN input is brought below VEN-H by VEN-HYS, the regulator stops running and enters Standby mode. Further decrease in the EN voltage to below VEN-VCC-L completely shuts down the device. This behavior is shown in Figure 8-3. The EN input can be connected directly to VIN if this feature is not needed. This input must not be allowed to float. The values for the various EN thresholds can be found in Section 7.5.

The LMR336x0AP-Q1 uses a reference-based soft start that prevents output voltage overshoots and large inrush currents as the regulator is starting up. A typical start-up waveform is shown in Figure 8-4, indicating typical timings. The rise time of the output voltage is about 4 ms (see Section 7.5).

GUID-AC831294-2A45-4367-B3C0-4A2A1C01C5DA-low.gifFigure 8-3 Precision Enable Behavior
GUID-2E688A25-A27C-4A85-B2B9-D7D4E254E21C-low.gifFigure 8-4 Typical Start-Up Behavior VIN = 12 V, VOUT = 5 V, IOUT = 3 A