Transient protection for 154V rails — what the ratings mean
The 1.5KE180CAH: It clamps a transient at 246V maximum when the surge current reaches 6.4A, and its 154V reverse standoff voltage means it sits across a nominal 154V DC bus without conducting in normal operation. The breakdown window starts at 171V minimum — so a transient that drives the line above that threshold triggers the avalanche, and the diode shunts the energy until the clamp voltage is reached. For a 1500W pulse, the 6.4A peak current is the limit; a higher surge would exceed the die's thermal capacity and risk failure.
The DO-201AA axial through-hole package (also known as DO-27) provides a robust mechanical anchor on the board — the lead bends absorb vibration better than a surface-mount package in high-shock automotive or industrial applications.