Last-buy status and what it means for your BOM
The 1.5KE170CA-E3/51: Vishay has marked the 1.5KE170CA-/51 as Last Buy — the manufacturer's last-time-buy window is closing, and once depleted no further production is scheduled. For a BOM line that depends on this specific TransZorb bidirectional TVS, the procurement decision is immediate: secure lifetime-buy inventory now through independent distribution, or plan a redesign around an active successor. The 6.4A peak pulse current rating defines the surge it can absorb before the junction exceeds the 175°C maximum operating temperature.
Clamping voltage and pulse-handling in a transient event
The DO-201AA (DO-27) axial-lead package handles the thermal dissipation through the leads into the PCB; mounting is through-hole, so the board's copper area and airflow set the effective derating at elevated ambient temperatures.