RF detector Schottky — 0.5 pF junction capacitance is the spec that matters
The Infineon BAT15-05W is a dual common-cathode Schottky diode pair in a SOT-323 package, designed specifically for RF mixer and detector circuits where junction capacitance loads the signal path. At 0 V bias and 1 MHz, the capacitance measures 0.5 pF — low enough to keep a 2.4 GHz front-end tuned without adding reactive loading that would shift the match. The 110 mA continuous current rating and 4 V peak reverse voltage confirm this is a small-signal device, not a power rectifier.
Why 0.5 pF and 4 V reverse define the application envelope
The 0.5 pF capacitance at 0 V is the key parameter for an RF detector: it sets the upper frequency limit before the diode's own capacitance begins to bypass the RF signal. In a typical zero-bias detector, the junction capacitance forms a low-pass filter with the source impedance — 0.5 pF into a 50-ohm system gives a -3 dB corner well above 6 GHz, so the diode works cleanly through the ISM bands at 2.4 GHz and 5.8 GHz. The 4 V peak reverse rating means the diode must never see a reverse bias above that level; in a mixer or detector the LO and RF voltages should be kept below 1 V peak each to stay within the safe operating area.
Package and marking — what to check on receipt
The BAT15-05W is supplied in the SC-70 / SOT-323 package. The supplier device package is SOT-323.