Vishay lists the 1.5KE51HE3/73 as Obsolete.
Automotive-grade TransZorb — what the ratings deliver
This is a 1500 W (1.5 kW) peak pulse power TransZorb TVS diode in the Vishay Automotive, AEC-Q101 series. The reverse standoff voltage is 41.3 V typ, so it sits across a 24 V or 28 V bus without conducting leakage in normal operation. Breakdown occurs at 45.9 V min, and clamping is held to 73.5 V max at the 20.4 A peak pulse current. That clamping ceiling protects downstream ECUs, sensors, and modules rated for 80 V or 100 V bus transients.
Package and temperature envelope
Housed in the DO-201AA / DO-27 axial-lead package, the 1.5KE51HE3/73 is a through-hole part — the lead bend and body length match the standard 1.5KE footprint used across the series.