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 suits under-hood and similar 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 (WD ENn) 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.