The 1.5KE350-B: With a 300 V reverse standoff voltage and a clamping ceiling of 506.1 V at 3.2 A peak pulse current, it protects 300 VDC rails from transient overvoltage events — the clamping voltage is the hard limit the downstream silicon sees. The operating junction temperature range spans -55°C to 175°C, covering industrial and telecom ambient conditions without derating at the high end. The DO-201AA axial-lead package (also known as DO-27) mounts through-hole — the lead length and board copper area set the thermal impedance for repetitive pulse trains, not just single-shot events.
Obsolete — sourcing through independent channels
Littelfuse lists the 1.5KE350-B as obsolete. The 1.5KE series is a broad TVS family with many voltage variants sharing the same 1500 W power class and DO-201 footprint. A pin-compatible replacement within the same series requires matching the standoff voltage (300 V) and unidirectional polarity — the 1.5KE350A (bidirectional) would not be a drop-in for this unidirectional part.