Peak pulse power and clamping performance
The 1.5SMCJ40CA_R1_00001: The 1500 W peak pulse rating (10/1000 µs waveform) is the number that sizes this part into a protection circuit — it tells you the diode survives a single-event transient of that energy without failing short. At that peak pulse current of 23.2 A, the clamping voltage tops out at 64.5 V, so the downstream load sees a hard ceiling of 64.5 V during the event.
Protection window — standoff, breakdown, and clamping
The reverse standoff of 40 V sets the continuous working voltage the diode can sit across without conduction — above it the device begins to avalanche. The minimum breakdown of 44.4 V gives you roughly a 5.6 V cushion above the standoff before the TVS starts clamping, so the protected rail can tolerate normal transients below that threshold without the diode engaging. That 40 V standoff makes this a natural fit for 24 V and 28 V industrial control rails — common fieldbus supply voltages that sit comfortably below the 44.4 V breakdown floor, leaving adequate headroom before the clamp activates.
Junction temperature and SMC footprint
Rated to 150°C maximum junction temperature — the SMC (DO-214AB) package thermal path runs through the cathode tab to the PCB pad, so the copper area under the device directly governs the thermal resistance and the continuous dissipation the part can handle between transients.
Series family and reel packaging
The 1.5SMCJ series spans a range of standoff voltages; this 40 V variant is available on tape-and-reel and cut-tape packaging to suit both high-volume assembly and low-quantity prototype runs.