Small-signal switching diode in a hermetic glass package
The 1N4148UR-1E3 is a standard switching diode from Microchip Technology, rated for 75 V DC reverse and 200 mA average rectified current. It switches in 20 ns typical reverse recovery time, making it a direct fit for high-speed clamping, snubbing, and general-purpose signal rectification where the 1N4148 electrical core is needed but in a surface-mount form. The DO-213AA package is a hermetic glass axial-lead outline reflowed into a surface-mount footprint — the same die as the through-hole 1N4148 but sealed for environments where moisture ingress or thermal cycling is a concern.
With 75 V reverse voltage and 200 mA forward current, the part comfortably handles 5 V, 12 V, or 24 V logic rails and low-current relay or LED loads. The 20 ns trr keeps switching losses negligible up into the low-MHz range — adequate for flyback snubbers on a 100 kHz converter or data-line protection. Forward voltage is 1.2 V max at 100 mA, so conduction drop is predictable across the operating range. Reverse leakage is only 500 nA at 75 V, preserving signal integrity in high-impedance nodes. Capacitance at 0 V bias is 4 pF — low enough that a series blocking diode in a 10 MHz signal path adds under 1 dB of insertion loss.
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DO-213AA is a standard JEDEC outline, so the footprint matches other hermetic glass diodes in the same package.