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

5 Pin Configuration and Functions

LMR36503E-Q1 9-Pin (2mm × 2mm) VQFN-HR RPE Package (Top View)
A. See Section 4 for more details. Pin 1 trimmed and factory-set for externally adjustable switching frequency RT variants only.
B. Pin 1 factory-set for fixed switching frequency MODE/SYNC variants only.
C. Pin 8 trimmed and factory-set for fixed output voltage VOUT/BIAS variants only.
D. Pin 8 factory-set for adjustable output voltage FB variants only.
Figure 5-1 9-Pin (2mm × 2mm) VQFN-HR RPE Package (Top View)
Table 5-1 Pin Functions
PIN TYPE DESCRIPTION
NO. NAME
1 RT
or MODE/SYNC		 A When the device is trimmed as the RT variant, the switching frequency can be adjusted from 200kHz to 2.2MHz.When the device is trimmed as the MODE/SYNC variant, the device can operate in user-selectable PFM/FPWM mode and can be synchronized to an external clock.
Do not float this pin.
2 PGOOD A Open-drain power-good flag output. Connect to a suitable voltage supply through a current limiting resistor. High = power OK, low = power bad. This pin goes low when EN = low. This pin can be open or grounded when not used.
3 EN/UVLO A Enable input to regulator. High = ON, low = OFF. Can be connected directly to VIN. Do not float this pin.
4 VIN P Input supply to regulator. Connect a high-quality bypass capacitor or capacitors directly to this pin and GND.
5 SW P Regulator switch node. Connect to power inductor.
6 BOOT P Bootstrap supply voltage for internal high-side driver. Connect a high-quality, 100nF capacitor from this pin to the SW pin.
7 VCC P Internal LDO output. Used as supply to internal control circuits. Do not connect to external loads. Can be used as logic supply for power-good flag. Connect a high-quality, 1µF capacitor from this pin to GND.
8 VOUT/BIAS or FB A Fixed output options are available with the VOUT/BIAS pin variant. Connect to output voltage node for fixed VOUT. Check Section 4 for more details.
The FB pin variant can help adjust the output voltage. Connect to tap point of feedback voltage divider. Do not float this pin.
9 GND G Power ground terminal. Connect to system ground. Connect to CIN with short, wide traces.
A = Analog, P = Power, G = Ground