Bidirectional TVS for 342 V rail protection
The 1.5KE400CA-E3/73: Its 342 V reverse standoff voltage makes it a fit for protecting 342 VDC or 240 VAC nominal rails against transients, with a minimum breakdown of 380 V and a clamping ceiling of 548 V at 2.7 A peak pulse current.
What the clamping voltage means for your rail
At 548 V max clamping, the TVS holds the transient below the typical 600 V rating of downstream electrolytic capacitors and semiconductor switches in a 342 V bus. The 2.7 A peak pulse current rating at the 10/1000 µs test waveform tells you the device can absorb a moderate-energy surge — a lightning-induced transient or inductive kickback — but not a direct lightning strike without additional series impedance. Through-hole DO-201AA axial package suits point-to-point wiring on terminal blocks or perfboard prototypes where surface-mount reflow is not an option.
Obsolete — sourcing through surplus channels
Vishay lists this part as obsolete. For a new design, a current-production bidirectional TVS in a similar voltage class and DO-201 package should be evaluated; the 1.5KE series has been widely second-sourced, but pin-to-pin compatibility must be checked against the original Vishay datasheet dimensions.