High-Voltage Buck Converter Selection for 48V & Industrial Power

In industrial control, automotive electronics, and distributed power systems, high-voltage buck converters directly impact efficiency, thermal stability, and long-term reliability. Selecting the right device requires balancing output current, topology, quiescent current, and safety qualification.

This guide compares three key devices from Texas Instruments’ LM501x family:

• LM5018MR/NOPB

• LM5017MRX/NOPB

• LM5013QDDARQ1

Core Parameter Comparison

• Input Voltage Range

  • LM5018: 7.5V–100V

  • LM5017: 7.5V–100V

  • LM5013: 6V–100V

• Maximum Output Current

  • LM5018: 300 mA

  • LM5017: 600 mA

  • LM5013: 3.5 A

• Topology

  • LM5018 / LM5017: Synchronous Buck

  • LM5013: Non-synchronous Buck

• Switching Frequency

  • Up to 1 MHz (all models)

• Quiescent Current (IQ)

  • LM5018 / LM5017: Low

  • LM5013: Ultra-low 1.2 µA

• AEC-Q100 Qualification

  • LM5013: Yes (Automotive Grade)

  • LM5017 / LM5018: No

Application Positioning

• LM5018 – Light-Load Efficiency Platform
  Ideal for measurement terminals, compact controllers, and IoT nodes requiring high efficiency at low output current and minimal thermal overhead.

• LM5017 – Mid-Power Industrial Standard
  Balances power density and efficiency for industrial control modules, LED drivers, and distributed power rails.

• LM5013 – Automotive & High-Current Design
  Supports 48V bus step-down architectures, MHEV/EV subsystems, ADAS, and vehicle control units requiring higher output current and automotive qualification.

Engineering Design Considerations

• Power Segmentation Strategy
  LM5013 targets high-current rails, while LM5017/LM5018 support low- to mid-power rails for modular system design.

• Topology Trade-Off

  • Synchronous designs improve light-load efficiency and reduce external components.

  • Non-synchronous architecture enhances robustness under heavy load and thermal stress.

• Thermal Optimization
  PowerPAD™ packaging improves heat dissipation and layout efficiency.

• Integrated Protection
  Overcurrent protection, thermal shutdown, UVLO; LM5013 additionally offers programmable current limit, soft-start, and enhanced protection for automotive systems.

• Layout Compatibility
  LM5017 and LM5018 are pin-compatible, enabling PCB reuse and easy power scaling.

Migration & Substitution Guidance

• LM5017 ↔ LM5018
  Same platform, different current levels. LM5018 improves efficiency in light-load or thermally constrained designs.

• LM5017 ↔ LM5013
  Upgrade path from industrial to automotive/high-current systems with minor thermal and driver adjustments.

• LM5018 ↔ LM5013
  Natural scaling from edge IoT nodes to 48V main bus power rails.

Engineering Takeaways

• LM5018 — Optimized for Light Load Efficiency

• LM5017 — Balanced Industrial Performer

• LM5013 — High-Current Automotive Solution

The LM501x family enables engineers to design scalable, thermally stable, and efficient power architectures across industrial and automotive environments.