SNVSBE0G October   2020  – May 2024 LMR43610-Q1 , LMR43620-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 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, and VOUT/FB Input
      6. 7.3.6  Bootstrap Voltage and VBOOT-UVLO (BOOT Terminal)
      7. 7.3.7  Output Voltage Selection
      8. 7.3.8  Spread Spectrum
      9. 7.3.9  Soft Start and Recovery from Dropout
        1. 7.3.9.1 Recovery from Dropout
      10. 7.3.10 Current Limit and Short Circuit
      11. 7.3.11 Thermal Shutdown
      12. 7.3.12 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
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Choosing the Switching Frequency
        2. 8.2.2.2  Setting the Output Voltage
          1. 8.2.2.2.1 FB for Adjustable Output
        3. 8.2.2.3  Inductor Selection
        4. 8.2.2.4  Output Capacitor Selection
        5. 8.2.2.5  Input Capacitor Selection
        6. 8.2.2.6  CBOOT
        7. 8.2.2.7  VCC
        8. 8.2.2.8  CFF Selection
        9. 8.2.2.9  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 Device Nomenclature
    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

8.2 Typical Application

Figure 8-1 shows a typical application circuit for the LMR436x0-Q1. This device is designed to function over a wide range of external components and system parameters. However, the internal compensation is optimized for a certain range of external inductance and output capacitance. As a quick-start guide, Table 8-1 and Table 8-2 provide typical component values for a range of the most common output voltages.

LMR43610-Q1 LMR43620-Q1 Example Application Circuit
A. The RT pin is factory-set for externally adjustable switching frequency RT variants only. Tying this pin to GND results in 2.2MHz switching frequency. See Section 7.3.3 for details.
B. The MODE/SYNC pin is factory-set for fixed frequency frequency MODE/SYNC variants only. Tying this pin to GND results in AUTO mode. See Section 7.3.2 for details.
Figure 8-1 Example Application Circuit
Table 8-1 Typical External Component Values for Adjustable Output LMR43620-Q1
ƒSW(1) (2) (kHz) VOUT (V) L (µH) NOMINAL COUT (RATED CAPACITANCE) RFBT (3) (kΩ) RFBB (kΩ) CIN CBOOT CVCC
400 3.3 10 3 × 22µF 33.2 14.3 4.7µF + 1 × 100nF 100nF 1µF
2200 3.3 2.2 2 × 22µF 33.2 14.3 4.7µF + 1 × 100nF 100nF 1µF
400 5 10 3 × 22µF 49.9 12.4 4.7µF + 1 × 100nF 100nF 1µF
2200 5 2.2 2 × 22µF 49.9 12.4 4.7µF + 1 × 100nF 100nF 1µF
(1) Inductor values are calculated based on typical VIN = 12V.
(2) The switching frequencies listed here can be achieved in a number of ways depending on the device variant. For RT devices see Section 7.3.3. For MODE/SYNC devices see Section 7.3.2.
(3) For RFBT and RFBB values outside the range stated above, see Section 8.2.2.2.1.
Table 8-2 Typical External Component Values for Fixed Output LMR43620-Q1
ƒSW(1) (2) (kHz) VOUT (V) L (µH) NOMINAL COUT (RATED CAPACITANCE) RFBT (kΩ) RFBB (3) (kΩ) CIN CBOOT CVCC
400 3.3 10 3 × 22µF 0 DNP 4.7µF + 1 × 100nF 100nF 1µF
2200 3.3 2.2 2 × 22µF 0 DNP 4.7µF + 1 × 100nF 100nF 1µF
400 5 10 3 × 22µF 0 DNP 4.7µF + 1 × 100nF 100nF 1µF
2200 5 2.2 2 × 22µF 0 DNP 4.7µF + 1 × 100nF 100nF 1µF
(1) Inductor values are calculated based on typical VIN = 13.5V.
(2) The switching frequencies listed here can be achieved in a number of ways depending on the device variant. For RT devices see Section 7.3.3. For MODE/SYNC devices see Section 7.3.2.
(3) DNP = Do Not Populate