SNVSCI9A June   2024  – September 2024 LMR36503E-Q1

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 (Automotive) Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 System Characteristics
    7. 6.7 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  Enable, Start-Up, and Shutdown
      2. 7.3.2  External CLK SYNC (with MODE/SYNC)
        1. 7.3.2.1 Pulse-Dependent MODE/SYNC Pin Control
      3. 7.3.3  Adjustable Switching Frequency (with RT)
      4. 7.3.4  Power-Good Output Operation
      5. 7.3.5  Internal LDO, VCC UVLO, and VOUT/BIAS Input
      6. 7.3.6  Bootstrap Voltage and VCBOOT-UVLO (CBOOT Terminal)
      7. 7.3.7  Output Voltage Selection
      8. 7.3.8  Soft Start and Recovery from Dropout
        1. 7.3.8.1 Recovery from Dropout
      9. 7.3.9  Current Limit and Short Circuit
      10. 7.3.10 Thermal Shutdown
      11. 7.3.11 Input Supply Current
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
        1. 7.4.3.1 CCM Mode
        2. 7.4.3.2 Auto Mode - Light Load Operation
          1. 7.4.3.2.1 Diode Emulation
          2. 7.4.3.2.2 Frequency Reduction
        3. 7.4.3.3 FPWM Mode - Light Load Operation
        4. 7.4.3.4 Minimum On-Time (High Input Voltage) Operation
        5. 7.4.3.5 Dropout
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 High Temperature Specifications
    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  Choosing the Switching Frequency
        3. 8.2.2.3  Setting the Output Voltage
          1. 8.2.2.3.1 FB for Adjustable Output
        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  CBOOT
        8. 8.2.2.8  VCC
        9. 8.2.2.9  CFF Selection
          1. 8.2.2.9.1 External UVLO
        10. 8.2.2.10 Maximum Ambient Temperature
      3. 8.2.3 Application Curves
    3. 8.3 Best Design Practices
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
        1. 8.5.1.1 Ground and Thermal Considerations
      2. 8.5.2 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
    1. 11.1 Tape and Reel Information

3 Description

The LMR36503E-Q1 is a 65V, 0.3A synchronous step-down DC/DC converter in 2mm × 2mm HotRod package. This easy-to-use converter can handle input voltage transients up to 70V, provide excellent EMI performance, and support fixed 3.3V, 5V and other adjustable output voltages.

The LMR36503E-Q1 uses peak current mode control architecture with internal compensation and maintains stable operation with minimal output capacitance. The wide input operating range of the LMR36503E-Q1 helps the device remain functional during a deep input voltage sag condition, making the device an excellent choice for automotive applications withstanding severe cold crank start impulses. The PGOOD flag in the LMR36503E-Q1 provides precise indication of the output voltage status, eliminating the requirement for an external supervisor. A seamless transition from FPWM to PFM, with an ultra-low standby quiescent current allows the LMR36503E-Q1 to support much higher system efficiency at low output loads. The MODE/SYNC pin variant helps to synchronize the LMR36503E-Q1 to an external clock. With the right resistor selection, the LMR36503E-Q1 RT pin variant can also be externally programmed to any desired switching frequency of operation. The rich feature set of the LMR36503E-Q1 is designed to simplify implementation for a wide range of automotive end equipments.

Package Information
PART NUMBERPACKAGE(1)PACKAGE SIZE(2)
LMR36503E-Q1RPE (VQFN-HR, 9)2.00mm × 2.00mm
(1) For more information, see Section 11.
(2) The package size (length × width) is a nominal value and includes pins, where applicable.
LMR36503E-Q1 Simplified SchematicSimplified Schematic
LMR36503E-Q1 Efficiency versus Output Current VOUT = 3.3V (Fixed), 2.2MHzEfficiency versus Output Current VOUT = 3.3V (Fixed), 2.2MHz