22V rail protection in a single SMA package
The SMAJ22CAE3/TR13 is a bidirectional Zener TVS diode from Microchip Technology, rated for a reverse standoff voltage of 22V and a peak pulse power of 500W (10/1000 µs waveform). That 22V standoff means it sits across a 22V nominal rail or signal pair and stays out of the way until a transient exceeds 24.4V breakdown — then it clamps at 35.5V max to shunt the surge. With a single bidirectional channel, one device protects a differential pair or a signal line referenced to ground, saving board space versus two unidirectional diodes.
Peak pulse power and clamping — what 500W means
The 500W peak pulse power rating is tested with a 10/1000 µs exponential waveform, a standard surge shape for telecom and industrial transient testing. At the 22V standoff level, the peak pulse current is 14.1A — that is the current the diode can handle before the clamping voltage rises to 35.5V. No power line protection (the device is not designed for AC mains) — it targets signal and DC rail protection where the surge energy is moderate.
Microchip lists the SMAJ22CAE3/TR13 as Active. No LTB notice or successor has been published, so this BOM line is safe for production builds.