The 1.5KE16CAL: It clamps both polarities from a single device, so it suits AC signal lines, bipolar DC rails, or any pair of traces where the surge polarity is unknown. The 13.6V standoff means it sits across a 12V nominal rail without conducting leakage in normal operation — the breakdown starts at 15.2V minimum, giving about 1.6V of headroom above the rail before the diode starts to avalanche. That margin keeps quiescent power dissipation near zero on a clean supply.
Package and rework — DO-201AD axial, through-hole
Housed in a DO-201AD axial leaded package, the 1.5KE16CAL is a through-hole part with a 0.052-inch (1.3 mm) diameter lead. The body is about 9.1 mm long — the leads bend to fit the board layout. It reworks cleanly under a soldering iron or hot air: the leads wick heat away from the junction, so the die stays below its 175°C junction limit during hand-soldering. Pin 1 is the cathode band; the bidirectional construction means orientation matters only for the band marking — the device clamps identically in both directions.
The 1500W peak pulse rating is specified at 25°C; derate linearly above that per the datasheet curve (typically 0.1%/°C above 25°C).