1500 W bidirectional Zener TVS — what it protects and how
The STMicroelectronics 1.5KE36CARL is a 1500 W peak-pulse-power bidirectional Zener TVS diode from the TRANSIL™ family, designed to clamp voltage transients on a nominal 30.8 V rail. It is a single-channel device in a DO-201AA axial-lead through-hole package, intended for general-purpose surge protection on power supplies, industrial controls, and telecom equipment where a through-hole part is preferred for its mechanical robustness and ease of board-level rework.
30.8 V standoff, 64.3 V clamp — sizing the protection margin
The 30.8 V reverse standoff voltage means this part sits across a 24 V or 28 V rail without conducting in normal operation, leaving headroom for steady-state tolerances. When a surge hits, the breakdown triggers at a minimum of 34.2 V and the clamp holds the peak at 64.3 V at the rated 156 A peak pulse current (8/20 µs waveform). That 64.3 V clamp is what the downstream circuitry must survive — if your DC-DC converter or load switch has a 60 V absolute maximum, this part leaves only a few volts of margin; a lower-clamp TVS would be a tighter fit.
1250 pF capacitance — signal-speed trade-off
At 1250 pF measured at 1 MHz, this is a high-capacitance TVS — fine for DC power rails and low-frequency signals, but it will load down a high-speed data line (CAN, RS-485, Ethernet) and distort the waveform. For signal-line protection at higher bit rates, a lower-capacitance TVS family (e.g., the STMicroelectronics SM series) is the better choice.
For new designs, a current-production bidirectional 1500 W TVS with a 30.8 V standoff in a DO-201 package — such as the 1.5KE36CA from the same TRANSIL family — should be evaluated as a functional replacement, though pin compatibility and electrical characteristics must be verified against the specific application.