Package and board integration — DO-213AB MELF footprint
The 1N5819UR-1/TR ships in the DO-213AB MELF (Metal Electrode Leadless Face) package, also designated LL41. This is a glass-passivated, hermetic barrel — the glass body seals the junction against moisture and ionic contamination, which matters for conformal-coated assemblies in humid or vacuum environments. The MELF footprint is cylindrical; the solder-paste stencil must be designed with a reduced aperture (typically 80% of the pad width) to prevent the component from rolling during reflow. The tape-and-reel format supports automated pick-and-place at standard feeder pitches.
Forward drop and switching speed — the Schottky advantage
This lower conduction loss improves efficiency in low-voltage rails (3.3 V, 5 V) where every 100 mV of diode drop eats into the output margin. The Schottky barrier is a majority-carrier device with no stored charge, so reverse recovery is inherently fast. The datasheet confirms recovery ≤ 500 ns at forward currents above 200 mA, making this diode suitable for switching frequencies above 100 kHz in flyback and boost converters.
Temperature grade and reverse leakage — derating for high-ambient designs
The junction operating range spans -65°C to 125°C, which qualifies the part for military/aerospace temperature cycling. At the cold end the forward drop increases slightly; at the hot end the reverse leakage dominates the thermal budget. Reverse leakage is specified at 50 µA maximum when the device blocks 45 V at 25°C. Schottky leakage doubles approximately every 10°C rise in junction temperature, so at 100°C ambient the leakage current can approach several milliamps. Designers should derate the reverse voltage or add a heatsink pad when the diode operates near its thermal limit.
Junction capacitance — signal-path loading
With 70 pF typical capacitance at 5 V reverse bias and 1 MHz, the 1N5819UR-1/TR loads a high-frequency signal line less than a standard 1 A Schottky in a larger package. This makes it usable as a clamping diode on data lines up to a few MHz, though the capacitance still exceeds what a dedicated TVS or RF Schottky would offer.
Microchip Technology lists the 1N5819UR-1/TR as Active. The part is in current manufacture and available through authorized distribution channels.