The STMicroelectronics 1.5KE30CA is a 1500 W bidirectional TVS diode from the 1.5KE series, designed to clamp voltage transients on power and signal lines. It is a through-hole device in a DO-201AA axial package, rated for a peak pulse current of 187 A under the 8/20 µs waveform.
The 28.5 V minimum breakdown voltage sets the threshold where the diode starts conducting — below that, the protected circuit sees the full transient. The 53.5 V clamping voltage is the maximum the load will see during a surge; if your downstream components (MOSFETs, ICs) have a lower absolute maximum rating, you need a lower-voltage TVS or additional protection. The 1500 W peak pulse power (1.5 kW) defines the energy the device can absorb in a single 10/1000 µs pulse — a 24 V supply rail with a 100 A surge would exceed this, so check your transient energy budget.
It replaces two unidirectional diodes in series, saving board space and parts count. The 1450 pF capacitance at 1 MHz is high enough that it may load high-speed data lines — keep it on power rails or low-frequency signals unless you verify signal integrity.