100 V Schottky in a SOT-323 — signal-level protection workhorse
The STMicroelectronics BAT46WFILM is a small-signal Schottky rectifier rated for 100 V DC reverse and 150 mA average forward current, housed in a surface-mount SOT-323 package. It is built for low-current, high-voltage applications where a Schottky's fast switching and low forward drop beat a standard silicon diode — think reverse-polarity blocking, flyback catch diodes, and OR-ing in battery-powered or portable equipment.
Forward drop and leakage — the trade-off at 100 V
Maximum forward voltage is 1 V at 250 mA, which is typical for a 100 V Schottky in this current class — the higher reverse voltage rating trades a slightly higher Vf compared to a 40 V Schottky. Reverse leakage is 5 µA at 75 V, a figure worth noting if the diode sits across a high-impedance node in a low-power design where leakage current could upset bias points. Junction capacitance is 10 pF at 0 V, 1 MHz, making this diode suitable for low-frequency switching and protection roles where capacitive loading is not a concern.
SOT-323 footprint — rework and layout notes
The SOT-323 (SC-70) package measures about 2.0 x 1.25 mm with a 0.65 mm pin pitch. It is small enough for dense layouts but still hand-solderable with a fine-tip iron or hot-air station — the thermal mass is low, so the joint wets quickly without cooking the board. No exposed pad, so no thermal-via planning needed.