Adjustable frequency with a synchronous buck, 5 V protected LDO, pulse-width window watchdog and power-on reset output
Allegro MicroSystems Europe has announced a new power management IC that can be configured as a buck or buck-boost pre-regulator to efficiently convert automotive battery voltages into a tightly regulated intermediate voltage complete with control, diagnostics, and protections. The output of Allegro’s A4413 supplies both a 5 V, 75 mA maximum high-voltage protected low drop-out (LDO) regulator for remote sensors, and a 0.8 to 3.3 V, 800 mA maximum adjustable synchronous buck regulator (ADJ). Designed to supply microprocessor power supplies in high-temperature environments, the device is ideal for under-hood and other automotive applications.
The A4413 can be enabled by its logic-level input (ENB) or its high-voltage input (ENBAT). Diagnostic outputs from the new device include a power-on-reset output with a 2 ms rising delay to monitor the synchronous buck, a power OK output to monitor the 5 V LDO, and an ENBAT status output (ENBATS). Dual bandgaps – one for regulation and one for fault detection – improve long-term reliability of the A4413.
The product also contains a pulse-width window watchdog (PWWD) timer that can be programmed to detect pulse widths from 1 to 2 ms. The watchdog timer has an activation delay that scales with the pulse-width setting to accommodate processor startup. The tolerance of the watchdog’s window can be set to ±8%, ±13%, or ±18% using the WD pin. The watchdog timer has an active-low enable pin (WDENn) to facilitate initial factory programming or field reflash programming.
Protection features include under- and overvoltage lockout on both output supply rails. In case of a shorted output, the LDO regulator features foldback overcurrent protection. In addition, the 5 V output is protected from a short-to-battery event. Both switching regulators include pulse-by-pulse current limit, hiccup mode short-circuit protection, LX (regulator output switching node) short-circuit protection to provide protection to the IC from damage in the case of accidental short-circuit from LX pins, missing asynchronous diode protection (VREG only), and thermal shutdown (TSD).
The A4413 is supplied in a low-profile 32-lead, 5 mm × 5 mm, 0.5 mm pitch QFN package (suffix “ET”) with exposed thermal pad.
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 has technical and marketing centres in Heidelberg and Hinterzarten in Germany. Allegro also has an engineering design centre in Edinburgh in Scotland and a technical and marketing centre in Annecy in France.