Wide input voltage inductor-less buck-boost automotive regulator
The device incorporates a multi-mode charge pump pre-regulator, followed by a 5V LDO. This enables operation with input voltages from 3.5 to 28V (with 40V protection), while maintaining a 5V output voltage. Compared to traditional LDO solutions, the efficiency across input range is improved, and VIN < VOUT operation is enabled. As opposed to traditional switching solutions no inductor, diode, or external switching element is required in this simple, low component-count optimised solution. Sleep-state current demand is specified as 1 µA typical.
The enable pin (ENB) is rated to operate at up to 40V, so it can be connected directly to VIN (e.g., vehicle battery). The IC includes an open-drain Power OK (POK) output, and protection features include input undervoltage lockout (UVLO), foldback overcurrent protection, output under/overvoltage protections (UV/OVP), and thermal shutdown (TSD). In addition, the output is protected from a short-to-battery event, which is a critical feature when driving loads connected via a wiring harness.
The A4480KLJTR-T device is available in an 8-pin eSOIC package with exposed pad for enhanced thermal dissipation.
Allegro MicroSystems; www.allegromicro.com
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