What the 1500W peak pulse rating means for your board
The 1.5KE27A/B: That 1500W figure is the maximum energy the device can clamp in a single surge event — it does not mean continuous dissipation. For a 23.1V standoff rail, the clamping voltage hits 37.5V at 40.5A peak pulse current, which keeps downstream silicon within its breakdown margin. The breakdown voltage range starts at 25.7V minimum, so the TVS begins conducting before the protected line exceeds 26V. This gives a guard band above the 23.1V reverse standoff where the part stays off during normal operation.
DO-201AA axial-lead package (also known as DO-27). Through-hole mounting — the leads are 0.96 mm diameter typical, and the body is 5.3 mm diameter by 7.6 mm long. The axial form factor means the part sits above the board; plan the lead bend radius and keep the body off the solder fillet to avoid stress cracking during thermal cycling. Operating temperature range is -55°C to 150°C junction, so it handles the full industrial and military temperature envelope without derating the peak pulse power at the high end.