Automotive buck regulator IC with wide input voltage range and low standby current

Designed to power the next generation of car audio and infotainment systems

The new A8585 from Allegro MicroSystems Europe is an automotive buck regulator IC that is designed to provide the low quiescent current power supply requirements of next-generation car audio and infotainment systems.

The new automotive AEC-Q100 qualified device incorporates all the control and protection circuitry required for a high-current regulator with ±1.0% output voltage accuracy. It operates over a wide input voltage range from 4 V to 35 V, and offers a choice of pulse width modulated (PWM) or pulse frequency modulated (PFM) operating modes.

In PWM mode, the device employs current-mode control to provide simple compensation, excellent stability, and fast transient response. In low IQ (quiescent current) mode, the A8585 employs pulse frequency modulation (PFM) to draw less than 33 µA from an input of 12 V while providing an output of 5.0 V/40 µA. Once operational, the A8585 will operate from an input voltage as low as 3.6 V (falling). The transition from PWM to PFM mode can be controlled by the user (A8585, A8585-1) or it can occur automatically (A8585-2, A8585-3).  Both versions offer fixed output voltage options of 3.3 V or 5 V with ±1.0% accuracy.

Other features of the A8585 include a programmable PWM switching frequency from 300 to 550 kHz which can be synchronised to an external clock. The A8585 has external compensation to optimise stability and transient response for a wide range of external components and applications. The device has a fixed soft start time of 5 ms.

The A8585 is designed to meet the most demanding requirements of automotive and non-automotive applications, with extensive protection features including pulse-by-pulse current limit, “hiccup” mode short-circuit protection, open/short asynchronous diode protection, boot open/short voltage protection, input undervoltage lockout, and thermal shutdown. EMI reduction features include frequency dithering and a controlled switching node.

The new regulator IC is targeted for the automotive and industrial markets with end applications to include automotive infotainment, instrumentation clusters, centre stack applications and advanced driver assistance systems.

The A8585KLKTR-T is available in a very small (4.9 mm × 6.0 mm) 10-lead SOIC package with exposed power pad. The package is lead (Pb) free, with 100% matt tin leadframe plating.

About Allegro
Allegro MicroSystems, LLC is a leader in developing, manufacturing and marketing high-performance semiconductors. Allegro's innovative solutions serve high-growth applications within the automotive market, with additional focus on office automation, industrial, and consumer/communications solutions. Allegro is headquartered in Worcester, Massachusetts (USA) with design, applications, and sales support centers located worldwide. Further information about Allegro can be found at www.allegromicro.com

Allegro MicroSystems Europe, headquartered in Chertsey, United Kingdom, is the European sales and marketing operation, and operates a network of representatives and distributors throughout Europe.  Allegro also has an engineering design centre in Edinburgh in Scotland and an application and marketing centre in Annecy in France.