Schottky diode, 40 V, 300 mA — the bench view
The STMicroelectronics BAT54JFILM is a small-signal Schottky rectifier rated for 40 V reverse voltage and 300 mA average forward current, housed in a SOD-323 surface-mount package. The 5 ns reverse recovery time (trr) tells you this is a fast-switching part — it recovers in the time it takes a typical 74HC gate to toggle once.
A 5 ns trr means the diode sweeps out stored charge fast enough that you won't see a reverse-recovery spike in a 500 kHz switching regulator. Compare that to a standard recovery rectifier in the same package — that part would still be conducting 100 ns later, dumping shoot-through current into the FET. The BAT54JFILM is the part you reach for when the board has a switching node that needs a clean catch diode and the layout is tight.
Active production, no end-of-life watch needed
ROHS3 compliance is confirmed, so it passes the environmental screening for EU and North American builds without an exemption review. No official second-source cross-reference is published, but the BAT54 family is widely second-sourced by multiple manufacturers in the same SOD-323 footprint; a direct pin-compatible swap from another brand is straightforward if dual-sourcing becomes a priority.
For volume production or urgent BOM fills, submit an RFQ with your target quantity and date code preference.