Switching regulator with wide voltage for automotive applications

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 optimising the output-inductor size. Pulse-by-pulse current sensing with digital frequency foldback in short-circuit minimises stress on power components to enhance reliability. Thermal protection is built-in, with shutdown and auto-recovery to minimise 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 analogue circuitry from an external source for optimum efficiency.

A synchronisation 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 5x6.4mm HTSSOP16 exposed-pad package, priced from $2.00 for orders of 1,000 pieces.