SNVA870A March   2019  – April  2020 LM25143 , LM25143-Q1 , LM5143 , LM5143-Q1 , LM5143A-Q1


  1.   LM5143-Q1 4-phase Buck Regulator Design for Automotive ADAS Applications
    1.     Trademarks
    2. 1 High Density Reference Design Description
      1. 1.1 Typical Applications
      2. 1.2 Features and Electrical Performance
    3. 2 Design Specifications
    4. 3 Application Circuit Diagram
    5. 4 Photo
    6. 5 Test Data and Performance Curves
      1. 5.1 Conversion Efficiency
    7. 6 EVM Documentation
      1. 6.1 Schematic
      2. 6.2 Bill of Materials
      3. 6.3 PCB Layout
    8. 7 Device and Documentation Support
      1. 7.1 Device Support
        1. 7.1.1 Development Support
      2. 7.2 Documentation Support
        1. 7.2.1 Related Documentation
          1. PCB Layout Resources
          2. Thermal Design Resources
  2.   Revision History

LM5143-Q1 4-phase Buck Regulator Design for Automotive ADAS Applications

With an input operating voltage as low as 3.5 V and up to 100 V as specified in Table 1, the LM5140-Q1, LM5141-Q1, LM5143-Q1, and LM5146-Q1 family of automotive synchronous buck controllers from TI provides flexibility, scalability, and optimized solution size for a range of applications. These controllers enable DC/DC solutions with high density, low EMI, and increased flexibility. All controllers are rated for a maximum operating junction temperature of 150°C and have AEC-Q100 grade 1 qualification.

Table 1. Automotive Synchronous Buck DC/DC Controller Family

LM5140-Q1 Dual 3.8 V to 65 V Peak current mode 5 V 180° phase shift N/A
LM5141-Q1 Single 3.8 V to 65 V Peak current mode 5 V N/A Yes
LM25141-Q1 Single 3.8 V to 42 V Peak current mode 5 V N/A Yes
LM5143-Q1 Dual 3.5 V to 65 V Peak current mode 5 V 90° phase shift Yes
LM5146-Q1 Single 5.5 V to 100 V Voltage mode 7.5 V 180° phase shift N/A

The LM5143-Q1 4-phase reference design is an automotive synchronous buck DC/DC regulator that employs synchronous rectification to achieve high conversion efficiency in a small footprint. It operates over a wide input voltage range of 8 V to 18 V, providing a regulated output of 5 V. The output voltage has better than 1% setpoint accuracy and is adjustable by installing appropriate feedback resistor values, letting you customize the output voltage from 1.8 V to 8 V as needed.

The module design uses the LM5143-Q1 65-V synchronous buck controller and has the following:

  • Wide input voltage (wide VIN) range
  • Wide duty cycle range
  • Peak current-mode PWM control loop
  • Integrated high-side and low-side MOSFET gate drivers
  • Cycle-by-cycle overcurrent protection
  • Configurable hiccup-mode protection
  • Spread spectrum modulation features

The free-running switching frequency is 2.1 MHz and is synchronizable to a higher or lower frequency if required. A synchronization output signal (SYNCOUT) from the master controller is 90° phase-shifted relative to its internal clock and drives the DEMB/SYNCIN pin of the slave controller. VCC voltage rail UVLO protects the converter at low input voltage conditions, and EN pins for each phase support application specific power-up and power-down requirements.

The LM5143-Q1 is available in a 40-pin VQFN package with 6-mm × 6-mm footprint to enable DC/DC solutions with high density and low component count. See the LM5143-Q1 3.5-V to 65-V dual synchronous buck DC/DC controller data sheet for more information. Use the LM5143-Q1 with the WEBENCH® Power Designer to create a custom regulator design. You can download the LM5143-Q1 Quickstart Calculator to optimize component selection and examine predicted efficiency performance across line and load ranges.