Buck regulator IC offers low quiescent-current standby mode

The A8580 from Allegro MicroSystems Europe is a buck regulator power-supply IC that offers a high degree of flexibility in input voltage (4 to 40 V), switching frequency (250 kHz to 2.4 MHz), and output current (up to 2.5 A). Designed to provide the power-supply requirements of next-generation car audio and infotainment systems, the new AEC Q100 qualified device incorporates all the control and protection circuitry required for a high-current regulator with ±1.0% output voltage accuracy. A key feature of the A8580 is the use of pulse-frequency modulation (PFM) to produce a very low input quiescent current while supplying a "keep alive" voltage supply in standby mode. The IC is guaranteed to draw less than 50 μA from a 12 V input while supplying 3.3 V at 40 μA. In addition, to work down to idle-stop battery conditions, the A8580 will operate down to at least 3.6 V input with the input voltage falling. Other features of the A8580 include switching frequency clock synchronization and an ultra-low current shutdown mode requiring less than 5 μA. The A8580 has external compensation to accommodate a wide range of frequencies and external components, and provides a power-on reset signal validated by the output voltage. Comprehensive protection features include pulse-by-pulse current limit, "hiccup" mode short-circuit protection, open/short asynchronous diode protection, "boot" pin open/short voltage protection, input undervoltage lockout, output overvoltage protection and thermal shutdown. The A8580 is supplied in a low-profile 16-pin TSSOP package (suffix LP) with exposed pad for enhanced thermal dissipation. Allegro