What the 600W pulse rating means for your rail
The P6KE6.8A is a unidirectional Zener TVS diode rated for 600W peak pulse power at the 10/1000µs waveform. That 600W rating defines how much transient energy the part can clamp before failure — for a 6.45V breakdown device, it translates to a peak current of 57A under the 8/20µs waveform. The 5.8V reverse standoff means the part stays off below that voltage; above it, the Zener clamps to 10.5V max. This is a through-hole axial part (T-18 package,) intended for general-purpose transient suppression on low-voltage DC rails.
onsemi lists the P6KE6.8A as Obsolete. For BOM lines that still call this exact order code, procurement must source through independent distribution or excess inventory channels. Confirm the axial T-18 footprint and unidirectional polarity match your board before committing.
Breakdown voltage and unidirectional polarity
Minimum breakdown voltage is 6.45V at the specified test current. The device is unidirectional — one Zener junction in a single axial lead orientation. For AC line protection, you would need a bidirectional pair or a different order code; this part is not rated for power line protection.