Allegro MicroSystems Announces Automotive Multi-Output PMIC With Buck Or Buck/Boost Pre-Regulator


Adjustable Frequency with a Synchronous Buck, 5 V Protected LDO, Pulse-Width Window Watchdog & NPOR

allAllegro MicroSystems, LLC 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 mAMAX high-voltage protected LDO for remote sensors (V5P), and a 0.8 to 3.3 V, 800 mAMAX adjustable synchronous buck regulator (ADJ). Designed to supply microprocessor power supplies in high-temperature environments, the A4413 is ideal for under hood and other automotive applications.

The A4413 can be enabled by its logic-level (ENB) or high-voltage (ENBAT) input. Diagnostic outputs from the A4413 include a power-on-reset output (NPOR) with a 2 ms rising delay to monitor the synchronous buck, a PowerOK output to monitor the 5 V LDO (POK5V), and an ENBAT status output (ENBATS). Dual bandgaps—one for regulation and one for fault detection—improve long-term reliability of the A4413.

The A4413 contains a pulse-width window watchdog (PWWD) timer that can be programmed to detect pulse widths from 1 to 2 ms (WDADJ). 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 WDTOL 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. It is priced at $2.24 in quantities of 1,000.

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