The 1.5KE24CAHE3_A/D: The 20.5 V reverse standoff voltage means this TVS will not conduct appreciably on a nominal 24 V supply rail, even with a 10 % overvoltage. The minimum breakdown voltage is 22.8 V, so the device starts clamping just above the normal operating range. Maximum clamping at 33.2 V limits the transient voltage seen by downstream components — a 24 V-rated ECU input sees a spike held to 33.2 V, well within the 40 V abs-max of most automotive-rated ICs. The 45.2 A peak pulse current rating (10/1000 µs) tells you the diode can sink a substantial surge — for a 24 V system, this handles load-dump transients from alternator field decay or inductive kickback from solenoids.
Through-hole axial — board-mount and rework
The DO-201AA axial package is a through-hole part with two leads — it mounts by soldering the leads into plated through-holes on the PCB. The axial form factor means it can be laid flat against the board or stood off with a spacer for better airflow. For rework, the axial leads are easy to desolder with a solder sucker or wick — the part lifts cleanly without pad damage, unlike surface-mount TVS packages that can lift pads under hot air. Pin 1 orientation is marked by the cathode band; the bidirectional version has no polarity, so orientation is non-critical.