SNVSC78B february   2022  – may 2023 LMQ66410 , LMQ66420 , LMQ66430

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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 System Characteristics
    7. 7.7 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Enable, Start-Up, and Shutdown
      2. 8.3.2  Adjustable Switching Frequency (with RT)
      3. 8.3.3  Power-Good Output Operation
      4. 8.3.4  Internal LDO, VCC, and VOUT/FB Input
      5. 8.3.5  Bootstrap Voltage and VBOOT-UVLO (BOOT Terminal)
      6. 8.3.6  Output Voltage Selection
      7. 8.3.7  Spread Spectrum
      8. 8.3.8  Soft Start and Recovery from Dropout
        1. 8.3.8.1 Recovery from Dropout
      9. 8.3.9  Current Limit and Short Circuit
      10. 8.3.10 Thermal Shutdown
      11. 8.3.11 Input Supply Current
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
        1. 8.4.3.1 CCM Mode
        2. 8.4.3.2 Auto Mode – Light Load Operation
          1. 8.4.3.2.1 Diode Emulation
          2. 8.4.3.2.2 Frequency Reduction
        3. 8.4.3.3 FPWM Mode – Light Load Operation
        4. 8.4.3.4 Minimum On-Time (High Input Voltage) Operation
        5. 8.4.3.5 Dropout
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Synchronous Buck Regulator at 400 kHz
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1  Choosing the Switching Frequency
        2. 9.2.3.2  Setting the Output Voltage
          1. 9.2.3.2.1 VOUT / FB for Adjustable Output
        3. 9.2.3.3  Inductor Selection
        4. 9.2.3.4  Output Capacitor Selection
        5. 9.2.3.5  Input Capacitor Selection
        6. 9.2.3.6  CBOOT
        7. 9.2.3.7  VCC
        8. 9.2.3.8  CFF Selection
        9. 9.2.3.9  External UVLO
        10. 9.2.3.10 Maximum Ambient Temperature
      4. 9.2.4 Application Curves
    3. 9.3 Best Design Practices
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
        1. 9.5.1.1 Ground and Thermal Considerations
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Device Nomenclature
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

9.2 Typical Application

For the circuit schematic, bill of materials, PCB layout files, and test results of an LMQ664x0 implementation see the LMQ66430-Q1 EVM. As a quick-start guide, Table 9-1 and Table 9-4 provide typical component values for a range of the most common output voltages.

Table 9-1 Typical External Component Values for Adjustable Output LMQ66430
ƒSW (kHz)(1) VOUT (V) L (µH) Nominal COUT (Rated Capacitance) Minimum COUT(Effective Capacitance)(2) RFBT (kΩ)(3) RFBB (kΩ) CIN CBOOT CVCC CFF(4)
400 3.3 10 3 × 22 µF 60 µF 33.2 14.3 4.7 µF DNP 1 µF 100 pF
2200 3.3 2.2 3 × 22 µF 60 µF 33.2 14.3 4.7 µF DNP 1 µF DNP
400 5 10 3 × 22 µF 60 µF 49.9 12.4 4.7 µF DNP 1 µF 100 pF
2200 5 2.2 3 × 22 µF 60 µF 49.9 12.4 4.7 µF DNP 1 µF DNP
(1) Inductor values are calculated based on typical VIN = 12 V.
(2) Minimum COUT values take into account the effects of DC bias voltage and temperature on the actual capacitance value.
(3) For RFBT and RFBB values outside the range stated above, see Section 9.2.3.2.1.
(4) See Section 9.2.3.8 for more information.
Table 9-2 Typical External Component Values for Adjustable Output LMQ66420
ƒSW (kHz)(1) VOUT (V) L (µH) Nominal COUT (Rated Capacitance) Minimum COUT(Effective Capacitance)(2) RFBT (kΩ)(3) RFBB (kΩ) CIN CBOOT CVCC CFF(4)
400 3.3 6.8 3 × 22 µF 60 µF 33.2 14.3 4.7 µF DNP 1 µF 100 pF
2200 3.3 2.2 2 × 22 µF 40 µF 33.2 14.3 4.7 µF DNP 1 µF DNP
400 5 6.8 3 × 22 µF 60 µF 49.9 12.4 4.7 µF DNP 1 µF 100 pF
2200 5 2.2 2 × 22 µF 40 µF 49.9 12.4 4.7 µF DNP 1 µF DNP
(1) Inductor values are calculated based on typical VIN = 12 V.
(2) Minimum COUT values take into account the effects of DC bias voltage and temperature on the actual capacitance value.
(3) For RFBT and RFBB values outside the range stated above, see Section 9.2.3.2.1.
(4) See Section 9.2.3.8 for more information.
Table 9-3 Typical External Component Values for Adjustable Output LMQ66410
ƒSW (kHz)(1) VOUT (V) L (µH) Nominal COUT (Rated Capacitance) Minimum COUT(Effective Capacitance)(2) RFBT (kΩ)(3) RFBB (kΩ) CIN CBOOT CVCC CFF(4)
400 3.3 22 2 × 22 µF 40 µF 33.2 14.3 4.7 µF DNP 1 µF 100 pF
2200 3.3 4.7 1 × 22 µF 20 µF 33.2 14.3 4.7 µF DNP 1 µF DNP
400 5 22 2 × 22 µF 40 µF 49.9 12.4 4.7 µF DNP 1 µF 100 pF
2200 5 4.7 1 × 22 µF 20 µF 49.9 12.4 4.7 µF DNP 1 µF DNP
(1) Inductor values are calculated based on typical VIN = 12 V.
(2) Minimum COUT values take into account the effects of DC bias voltage and temperature on the actual capacitance value.
(3) For RFBT and RFBB values outside the range stated above, see Section 9.2.3.2.1.
(4) See Section 9.2.3.8 for more information.
Table 9-4 Typical External Component Values for Fixed Output LMQ66430
ƒSW (kHz)(1) VOUT (V) L (µH) Nominal COUT (Rated Capacitance) Minimum COUT(Effective Capacitance)(2) RFBT (Ω) RFBB (Ω)(3) CIN CBOOT CVCC CFF
400 3.3 10 3 × 22 µF 60 µF 0 DNP 4.7 µF DNP 1 µF DNP
2200 3.3 2.2 2 × 22 µF 40 µF 0 DNP 4.7 µF DNP 1 µF DNP
400 5 10 3 × 22 µF 60 µF 0 DNP 4.7 µF DNP 1 µF DNP
2200 5 2.2 2 × 22 µF 40 µF 0 DNP 4.7 µF DNP 1 µF DNP
(1) Inductor values are calculated based on typical VIN = 12 V.
(2) Minimum COUT values take into account the effects of DC bias voltage and temperature on the actual capacitance value.
(3) DNP = Do Not Populate.
Table 9-5 Typical External Component Values for Fixed Output LMQ66420
ƒSW (kHz)(1) VOUT (V) L (µH) Nominal COUT (Rated Capacitance) Minimum COUT(Effective Capacitance)(2) RFBT (kΩ) RFBB (kΩ)(3) CIN CBOOT CVCC CFF
400 3.3 6.8 3 × 22 µF 60 µF 0 DNP 4.7 µF DNP 1 µF DNP
2200 3.3 2.2 2 × 22 µF 40 µF 0 DNP 4.7 µF DNP 1 µF DNP
400 5 6.8 3 × 22 µF 60 µF 0 DNP 4.7 µF DNP 1 µF DNP
2200 5 2.2 2 × 22 µF 40 µF 0 DNP 4.7 µF DNP 1 µF DNP
(1) Inductor values are calculated based on typical VIN = 12 V.
(2) Minimum COUT values take into account the effects of DC bias voltage and temperature on the actual capacitance value.
(3) DNP = Do Not Populate.
Table 9-6 Typical External Component Values for Fixed Output LMQ66410
ƒSW (kHz)(1) VOUT (V) L (µH) Nominal COUT (Rated Capacitance) Minimum COUT(Effective Capacitance)(2) RFBT (kΩ) RFBB (kΩ)(3) CIN CBOOT CVCC CFF
400 3.3 22 2 × 22 µF 40 µF 0 DNP 4.7 µF DNP 1 µF DNP
2200 3.3 4.7 1 × 22 µF 20 µF 0 DNP 4.7 µF DNP 1 µF DNP
400 5 22 2 × 22 µF 40 µF 0 DNP 4.7 µF DNP 1 µF DNP
2200 5 4.7 1 × 22 µF 20 µF 0 DNP 4.7 µF DNP 1 µF DNP
(1) Inductor values are calculated based on typical VIN = 12 V.
(2) Minimum COUT values take into account the effects of DC bias voltage and temperature on the actual capacitance value.
(3) DNP = Do Not Populate.