ST: switching regulator with wide voltage ranges

The STMicroelectronics A7987 automotive switching regulator has a wide input-voltage range that allows use in trucks and buses, and an adjustable output voltage that ensures flexibility and stable performance to power the numerous voltage rails in automotive applications such as body infotainment and telematics.

With maximum input voltage of 61V, the A7987 can operate from a 24V battery in a conventional or hybrid/electric vehicle and maintain a regulated output despite disturbances such as load-dump. The output is adjustable from 0.8V up to the input voltage, with low dropout, and can provide up to 3A for a wide variety of loads from logic to lighting.

The current limit and switching frequency up to 1.5MHz are set with external pulldown resistors, letting designers create compact power modules by optimizing the output-inductor size. Pulse-by-pulse current sensing with digital frequency foldback in short-circuit minimizes stress on power components to enhance reliability. Thermal protection is built-in, with shutdown and auto-recovery to minimize reliance on external intervention.

The A7987 embeds a low-resistance N-channel power MOSFET. At light load, pulse skipping maintains output regulation and a bias-voltage input with integrated switchover allows powering analog circuitry from an external source for optimum efficiency.

A synchronization pin allows up to five regulators to coexist by switching out of phase to avoid noise effects and reduce the RMS current flowing in the input capacitor. An Enable pin and a Power-Good indicator with adjustable delay permit power-up sequencing. There is also an adjustable soft-start function to limit inrush current. AEC-Q100 certified, the A7987 switching regulator is in production now, in a 5mm x 6.4mm HTSSOP16 exposed-pad package.

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