What this 600 W bidirectional Zener does on the board
The P6KE350CA-T: The bidirectional structure means a single device protects both polarities on a balanced line (RS-485, CAN, audio) without needing two diodes back-to-back.
Voltage thresholds and the 300 V standoff decision
Breakdown starts at 332 V minimum, so there is 32 V of headroom before the diode begins to avalanche.
Through-hole DO-15 axial — board-fit and temperature range
Housed in a DO-204AC (DO-15) axial-lead package, the P6KE350CA-T mounts through-hole — the leads bend into the PCB pads, and the body stands off the board. The axial format is common in telecom line cards and industrial power supplies where wave-solder assembly is standard.
Obsolete — sourcing through independent channels
Diodes Incorporated lists the P6KE350CA-T as obsolete — the manufacturer no longer produces it. Available through independent surplus and broker channels.