The Infineon BAS40-05W is a Schottky barrier diode array containing two diodes in a common-cathode configuration, housed in a PG-SOT323-3 surface-mount package. Schottky diodes switch fast with low forward voltage drop — here 1 V max at 40 mA per diode — making them useful for high-speed rectification, polarity protection, and clamping in low-voltage DC rails up to 40 V reverse. Each diode handles 120 mA average rectified current, and the pair shares the cathode pin, so it fits circuits needing two diodes with a common return.
Reverse voltage is rated 40 V DC max — that is the ceiling for the blocking voltage; keep the rail below that with margin.
Package and footprint — what to expect
The BAS40-05W comes in a PG-SOT323-3 package (also known as SC-70). It is a three-pin surface-mount part: two anodes and one common cathode. The body is small — roughly 2.0 mm x 1.25 mm — so it fits tight layouts but needs a steady hand for rework. No lab bench required, but a fine-tip iron and magnification help. MSL rating is not in the record, but SOT-323 devices are typically MSL 1, so moisture sensitivity is rarely an issue.