1500W bidirectional TVS — what the voltage stack means for the rail
The 1.5KE250CARL is a bidirectional Zener TVS diode from ST's TRANSIL™ 1.5KE family, packaged in a DO-201AA / DO-27 axial through-hole body. It is a general-purpose surge suppressor rated for a peak pulse power of 1500W (1.5kW) per the 10/1000µs waveform, with a single bidirectional channel that clamps transients of either polarity. Breakdown occurs at a minimum of 237V, and clamping is specified at a maximum of 442V at the rated peak pulse current of 23A (8/20µs waveform). For a 230V AC line or a 200V DC bus, the 213V standoff leaves enough headroom to avoid nuisance triggering during normal operation, while the 442V clamp keeps the transient voltage below the typical 500V–600V withstand of downstream power semiconductors or DC-link capacitors.
STMicroelectronics lists the 1.5KE250CARL as Active.
Through-hole axial — rework and panel-mount compatible
The DO-27 axial package is through-hole, which means it solders into a plated through-hole on the PCB or can be wired into a terminal block for panel-mount surge protection. The 280pF typical capacitance at 1MHz is worth noting on high-speed data lines — it loads the signal with enough capacitance to round edges on anything above a few hundred kHz, so this part is better suited to power rails and slow I/O than to Ethernet or CAN bus.