Allegro MicroSystem's synchronous buck regulator IC drives automotive power applications



The A8650 from Allegro MicroSystems Europe is a robust synchronous buck regulator IC designed for automotive power-supply applications in areas such as instrument clusters, HVAC, navigation, and audio systems. The AEC Q100 qualified device is an adjustable-frequency, high output current, PWM regulator that integrates a high-side P-channel MOSFET and a low-side N-channel MOSFET. It incorporates current-mode control to provide simple compensation, excellent loop stability, and fast transient response. Key features of the A8650 include a switching frequency that is externally adjustable from 250 kHz to 2.4 MHz, an externally set soft-start time to minimise inrush currents, an enable/synchronisation input to either turn the output voltage on or off and/or synchronise the PWM switching frequency, and a "power OK" output to indicate when the output voltage is within its regulated limits. The sleep mode current of the A8650's control circuitry is less than 3 μA. Protection features include input undervoltage lockout, cycle-by-cycle overcurrent protection, "hiccup" mode short-circuit protection, overvoltage protection, and thermal shutdown. In addition, the A8650 provides open-circuit, adjacent pin short-circuit, and short-to-ground protection at every pin to satisfy the most demanding automotive applications. The A8650 uses external compensation to accommodate a wide range of power components to optimise transient response without sacrificing stability. It regulates input voltages from 2.5 V to 5.5 V down to output voltages as low as 0.8 V, and is able to supply at least 2 A of load current. The A8650 is available in a 10-pin eMSOP package (suffix LY) with exposed pad for enhanced thermal dissipation. Allegro MicroSystems