STMicro Automotive Switching Regulator Supports Wide-Input Voltages, Multiple Reliability Features

June 25, 2019 Brandon Lewis

STMicro has released a wide-input voltage range automotive switching regulator for trucks and buses, the A7987. With a maximum input voltage of 61V, the A7987 can be driven by 24V batteries while an adjustable output from 0.8V can deliver up to 3A for a wide variety of loads.

A current limit and switching frequency of up to 1.5 MHz on the A7987 are set with external pulldown resistors, enabling optimized output-inductor footprints that lead to compact power module designs. Meanwhile, a bias-voltage input with integrated switchover allows analog circuitry to be powered from an external source.

The A7987’s adjustable output voltage, with low dropout, ensures stability over the numerous voltage rails in automotive applications. Additional stability and reliability features include:

  • An integrated low-resistance N-channel power MOSFET and pulse skipping for enhanced output regulation
  • Pulse-by-pulse current sensing that includes digital frequency foldback
  • Built-in thermal protection with shutdown and auto-recovery 
  • A synchronization pin supporting up to five regulators enables switching out of a given phase to avoid noise and reduce RMS current
  • Adjustable soft-start function limits inrush current
  • An enable pin and power-good indicator with adjustable delay provide power-up sequencing capabilities

The A7987 switching regulator is available in an AEC-Q100, 5 mm x 6.4 mm HTSSOP16 exposed-pad package. The devices can be evaluated today using the STEVAL-ISA207V1.  

More information is available at

About the Author

Brandon Lewis

Brandon Lewis, Editor-in-Chief of Embedded Computing Design, is responsible for guiding the property's content strategy, editorial direction, and engineering community engagement, which includes IoT Design, Automotive Embedded Systems, the Power Page, Industrial AI & Machine Learning, and other publications. As an experienced technical journalist, editor, and reporter with an aptitude for identifying key technologies, products, and market trends in the embedded technology sector, he enjoys covering topics that range from development kits and tools to cyber security and technology business models. Brandon received a BA in English Literature from Arizona State University, where he graduated cum laude. He can be reached by email at

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