Buck regulator IC with ultra-low IQ for automotive infotainment

February 24, 2016 // By Paul Buckley
Allegro MicroSystems Europe's A8591 a buck regulator IC is designed to meet the power-supply requirements of the latest automotive infotainment systems. The device is available in fixed 5 V or 3.3 V regulated output voltage configurations.

The AEC-Q100 qualified device provides all the control and protection circuitry of a 2 A regulator circuit with ±1% output voltage accuracy. An ultra-low-IQ mode employs pulse-frequency modulation (PFM) to draw less than 33 µA from a 12 V input while supplying a 5 V/40 µA output, making the A8591 ideal for automotive battery-powered 'keep-alive' applications.

A 'sleep' feature is included which reduces the standby current down to 5 µA. When operational, the A8591 operates down to at least 3.6 V input to accommodate idle-stop battery input requirements. The regulator PWM switching frequency can be set between 300 kHz and 2.4 MHz and 'dithered' or synchronised to an external clock.

The A8591 has extensive protection features including pulse-by-pulse current limit, 'hiccup' mode short-circuit protection, open/short-circuit asynchronous diode protection, boot open/short-circuit voltage protection, input-voltage undervoltage lockout, power-on reset (NPOR), and thermal shutdown.

The regulator is targeted at the automotive and industrial markets, including applications such as infotainment, centre stack and instrument clusters, advanced driver assistance systems (ADAS), head-up displays, HVAC systems and industrial controls.

The A8591 is supplied in a 3 mm × 3 mm 10-pin wettable flank DFN package (suffix EJ) with exposed power pad for enhanced thermal dissipation. It is lead (Pb) free, with 100% matt-tin leadframe plating.