Pololu Step-Down Voltage Regulator - 8.4V, 5A

The Pololu D42V55F8 is a compact synchronous step-down (buck) switching regulator that takes input voltages from 8.4 V up to 60 V and delivers a regulated 8.4 V output at up to 5 A. A step-down converter reduces a higher input voltage to a lower output voltage while increasing the available current and doing so far more efficiently than a linear regulator; this means less heat and better energy use in high-difference applications.

The board supports typical continuous output currents between 3.5 A and 7 A, depending on input voltage and thermal conditions. Efficiency ranges from approximately 80% to 95%, varying with load and voltage differential. It operates at around 400 kHz switching frequency under heavy loads, with ultra-low quiescent current (< 0.2 mA) at no load.

Features include an enable (EN) input for low-power shutdown, a power-good (PG) output for voltage monitoring and sequencing, soft-start to limit inrush current, and built-in reverse-voltage, over-current, and over-temperature protection. The module measures 1″ × 1″ × 0.355″ (25.4 × 25.4 × 9 mm), includes three mounting holes for #2 or M2 screws, and exposes six 0.1″ grid-compatible connections (VIN, VOUT, GND, VRP, EN, PG) with duplicated power rails for easy prototyping.