What this 1500 W axial TVS does on the board
The 1.5KE22-B: It clamps transients at 32.13 V maximum when the surge current hits 49.7 A, protecting downstream silicon from overvoltage events like inductive kickback, lightning-coupled surges, or ESD strikes on a 18.8 V nominal rail. The reverse standoff voltage of 18.8 V means the diode stays high-impedance below that level and only starts conducting when the transient exceeds the 19.8 V minimum breakdown threshold.
Package, mounting, and temperature range
Housed in a DO-201AA / DO-27 axial-lead package (supplier device package DO-201), the 1.5KE22-B is a through-hole part intended for hand-insertion or wave-solder assembly. The axial leads let it sit flat against the board or stand off for better airflow — the thermal path is through the leads, so the copper pad area on the PCB matters for derating at high ambient.
Sourcing an obsolete TVS diode
Littelfuse lists the 1.5KE22-B as obsolete. No pin-compatible direct replacement from Littelfuse has been published, so a BOM substitution would require verifying the clamping voltage and package fit against the original design.