Inductorless Buck-Boost from Allegro Drives Automotive Sensors with Reduced BoM

Schematic of Allegro A4480 Buck-Boost Converter

5Vout at 50mA with short circuit protection and operation down to 3.5Vout

The analog experts at Allegro MicroSystems have recently introduced a 5Vout regulator with wide Vin.  They designed this to power sensors used in automotive applications, but it is also for low-end microcontrollers and other non-automotive applications where there might be a need for a wide-Vin range.

The A4480 from Allegro integrates charge pump pre-regulator with multi-mode with a 5V LDO after. This give them the ability to hold the 5V output with an input range of 3.5V to 28V. This device also comes with 40V protection. When you stack this up against traditional LDO’s, the efficiency numbers across the input range are better, and Vin < Vout operation is enabled. Also, if you compare this to a switching solution, you don’t need a diode, inductor, or MOSFET for this simple LDO with low-component count and optimised BoM. To run this directly off of a car battery, the enable pin (ENB) is spec’ed to operate up to 40V. This chip also has an open-drain Power OK (POK) out, and features to protect the device such as under voltage lockout (UVLO), output under/over voltage protection (UV/OVP), fold back over current protection, and thermal shutdown (TSD). To add to the protection features, they also protected the output from short-to-battery events, which is a nice addition when you drive loads connected to harnesses.

The part number will be A4480KLJTR-T.  It is available in an 8-pin eSOIC package with an exposed pad for better heat dissipation.  Of course, it is lead-free, with 100% matt tin lead frame plating.

Price:  .94/1k QTY
Lead Time:  10 Weeks