The SMAJ70CAE3/TR13 is a bidirectional Zener TVS diode from Microchip Technology, rated for 500W peak pulse power per the 10/1000µs waveform. It clamps at 113V max when the surge current hits 4.4A, with a minimum breakdown voltage of 77.8V. The 70V reverse standoff means it sits on a 70V rail without conducting at steady state.
The 500W peak pulse power is the energy the part can absorb in a single surge event without failing. For a 70V rail, the 77.8V min breakdown ensures the TVS does not leak at nominal voltage, while the 113V clamp limits the overvoltage seen by downstream components. The 4.4A peak pulse current is the current the part can shunt during the surge. Bidirectional channels = 1 means the part clamps both polarities with a single device, saving board space compared to back-to-back unidirectional TVSs.