5 ns reverse recovery — what it buys the switching design
The BAT54SFILM is a small-signal Schottky diode from STMicroelectronics, configured as a series pair of two diodes in a single SOT-23-3 package. Its 5 ns reverse recovery time (trr) is the headline switching-speed spec — that is the time the diode takes to turn off after forward bias, and at 5 ns it is fast enough for high-frequency rectification, clamping, and steering in power supplies, DC-DC converters, and signal-conditioning circuits where a standard recovery diode would cause excessive switching loss or ringing. The 1 µA reverse leakage at 30 V is typical for a Schottky of this voltage class — low enough for most signal and low-power rail applications, but worth checking if the circuit runs from a battery or a high-impedance sense node where leakage current matters. The 150°C max junction is the thermal limit for derating — if the diode sits near a hot regulator or in a high-ambient enclosure, the forward current and power dissipation need to be derated per the thermal curve.
SOT-23-3 dual diode — footprint and fit
The BAT54SFILM comes in the industry-standard SOT-23-3 surface-mount package. The series-connected pair of Schottky diodes shares the same three-pin footprint as many other dual-diode SOT-23 parts, so the board layout is straightforward and the part is a drop-in for common-cathode or common-anode series configurations. The SOT-23-3 body is small enough for dense PCB layouts but still large enough for manual rework with a fine-tip iron or hot-air station.