Automotive-qualified buck regulator powers infotainment

March 07, 2016 // By Susan Nordyk
AEC-Q100-qualified for automotive use, the A8591 2-A buck regulator from Allegro MicroSystems provides an output voltage that is accurate to within ±1%. Robust protection features make the A8591 useful for automotive infotainment systems, advanced driver-assistance systems, heads-up displays, and instrument clusters.

The A8591 employs pulse-frequency modulation to draw less than 33 µA from a 12-V input, while supplying an output of 5V, 40 µA. A sleep function drops standby current to 5 µA. When operational, the regulator operates down to at least a 3.6-V input to accommodate idle-stop battery-input requirements. PWM switching frequency can be set between 300 kHz and 2.4 MHz and dithered or synchronised to an external clock.


Protection features of the A8591 regulator include pulse-by-pulse current limit, hiccup-mode short-circuit protection, open/short asynchronous diode protection, boot open/short voltage protection, and input undervoltage lockout. The device also provides thermal shutdown and withstands load dump surges up to 40 VIN. In addition to automotive applications, the A8591 regulator is suitable for network, telecommunication, and industrial markets.


Housed in a thermally enhanced 3×3-mm, 10-pin DFN package, the A8591 costs $1.54 (1000).


Allegro MicroSystems,