SNVAA32 july   2023 LMQ644A2-Q1

 

  1.   1
  2.   LMQ644A2-Q1 6-Phase Buck Regulator Design for Automotive ADAS Applications
  3.   Trademarks
  4. 1 Introduction
    1. 1.1 Features and Electrical Performance
  5. 2Design Specifications
  6. 3Application Circuit Diagram and Operating Configuration Table
  7. 4Top and Bottom Board Views
  8. 5Test Data and Performance Curves
    1. 5.1 Conversion Efficiency
    2. 5.2 Operating Waveforms
      1. 5.2.1 6-phase Switching
      2. 5.2.2 Load Transient Response
      3. 5.2.3 Loop Response
      4. 5.2.4 Startup/Shutdown
    3. 5.3 Thermal Performance
    4. 5.4 CISPR 25 EMI Performance
  9. 6EVM Documentation
    1. 6.1 Schematic
    2. 6.2 Bill of Materials
    3. 6.3 PCB Layout
  10. 74-Phase Configuration
    1. 7.1 4-Phase Switching
  11. 8Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
    2. 8.2 Documentation Support
      1. 8.2.1 References
        1. 8.2.1.1 PCB Layout Resources
        2. 8.2.1.2 Thermal Design Resources

2 Design Specifications

Table 2-1 Electrical Performance Characteristics
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
INPUT CHARACTERISTICS
Input voltage range, VIN(3) Operating(2) 3 12 20 V
Transients 3 36
Input current, no load, IIN(NL) IOUT = 0 A, AUTO mode (Resistive leak paths are removed) VIN = 9 V 49 uA
VIN = 12 V 38
VIN = 16 V 28
Input current, disabled, IIN(OFF) VEN = 0 V (Resistive leak paths are removed) VIN = 12 V 2.8 µA
OUTPUT CHARACTERISTICS
Output voltage, VOUT(1) 3.135 3.3 3.465 V
Output current, IOUT VIN = 3.8 V to 20 V 0 36 A
Output voltage regulation, ΔVOUT Load regulation IOUT = 0 A to 36 A 0.5%
Line regulation VIN = 9 V to 16 V 0.5%
Output voltage ripple, VOUT(AC) VIN = 12 V, IOUT = 36 A 20 mVrms
Soft-start time, tSS CSS = 100 nF 4 ms
SYSTEM CHARACTERISTICS
Switching frequency, FSW VIN = 12 V 320 400 480 kHz
Full load efficiency, ηFULL IOUT = 36 A VIN = 8 V 91.6%
VIN = 12 V 91.5%
VIN = 16 V 90.9%
(1) The default output voltage of this design is 3.3 V. Efficiency and other performance metrics can be changed based on operating input voltage, load current, externally-connected output capacitors, and other parameters.
(2) The recommended airflow when operating is 200 LFM.
(3) Minimum 3.85V VIN for 2.5V VOUT, 4.23V VIN for 3.3V VOUT, 5.45V VIN for 5V VOUT