What this Schottky diode pair does
The Infineon BAT 54-05 B5003 is a Schottky diode with two diodes in a common-cathode configuration, housed in a SOT-23-3 surface-mount package. The 5 ns reverse recovery time makes it suitable for high-speed switching applications like polarity protection, freewheeling, and clamping in low-power DC circuits.
Lifecycle status — obsolete, sourced to order
The 200 mA per-diode average current handles small-signal loads like relay coils, logic-level switching, and signal clamping. Forward voltage drops 800 mV at 100 mA, which is typical for a Schottky at this current level and gives a lower forward loss than a standard silicon diode. Reverse leakage is 2 µA at 25 V, acceptable for most low-power circuits but worth noting if the diode sits across a high-impedance node in a battery-powered design.
The SOT-23-3 package (also known as TO-236-3 or SC-59) is a standard three-lead surface-mount footprint. The supplier device package is PG-SOT23. This is a common, easily laid-out package for low-power discrete diodes.