Discrete
Switching Diodes
General-purpose fast-recovery signal diodes for steering, clamping, and small-signal rectification.
What is it?
Switching diodes (also called signal diodes or general-purpose diodes) are low-power diodes optimised for fast switching speed and low forward voltage drop. The classic part is 1N4148; common SMD families include BAV99 (dual), BAS70 (Schottky), and BAS40. Used wherever you need a one-way path for small currents — typically up to a few hundred milliamps.
When do you need it?
- Signal-level rectification (peak detectors, demodulators).
- Diode-OR logic gating multiple sources to one rail.
- Clamping flyback voltage on low-current relays or solenoids.
- Voltage-level shifting via diode drops.
- Reverse-polarity protection on low-current inputs.
How to pick the right one
- Forward current (IF)
- Choose at least 2× your continuous current. Common: 200 mA (BAV99), 500 mA (BAS40).
- Reverse voltage (VR)
- Higher than the maximum reverse voltage in your circuit. 70 V / 100 V / 200 V common.
- Forward voltage (VF)
- Standard silicon ~0.7 V, Schottky variants ~0.3-0.4 V. Schottky saves power but has higher reverse leakage.
- Reverse recovery time (Trr)
- Critical for >10 MHz switching. Fast switching diodes have Trr < 10 ns.
- Configuration
- Single (SOD-323), dual common-anode / common-cathode / series (SOT-23, SOT-363, SC-88).
What Magnias offers
Magnias offers the full switching-diode lineup: 1N4148W (single fast), BAV99 / BAS40 / BAS70 (dual in SOT-23 / SC-88 / SOT-363), in standard and AEC-Q101 versions. Bare-die and packaged options available.
Common questions
BAV99 or BAW56?
Both dual diodes in SOT-23. BAV99 = series connection (cathode-to-anode), BAW56 = common-anode. Pick based on circuit topology.
When to use Schottky instead of standard silicon?
When you need low VF (<0.4 V) to save power, or fast switching with no reverse recovery (>1 MHz). Avoid Schottky when high reverse voltage (>40 V) or low leakage is needed.
Why is 1N4148 still so popular?
Cheap, fast (Trr ~4 ns), wide availability, well-characterised over 50+ years. For a generic small-signal diode it's hard to beat.