Zener TVS diode for 5.8 V rail protection
The 1.5KE6.8ARL4G: The -65°C to 175°C operating junction temperature range covers military and industrial thermal extremes — the 175°C TJ(max) is the absolute-maximum junction temperature, not the ambient. For a 5.8 V working voltage, the reverse standoff of 5.8 V (typ) means the diode does not conduct at the normal rail voltage; breakdown starts at 6.45 V min, so the rail must stay below that to avoid leakage.
Obsolete — sourcing through independent channels
Littelfuse lists the 1.5KE6.8ARL4G as Obsolete. No pin-compatible direct replacement from Littelfuse has been published; a parametric match from another manufacturer would require board-level re-qualification. The DO-201AD axial package is a standard through-hole form factor — the same footprint serves many TVS diodes in the 1500 W class, so a replacement part with the same package and similar clamping voltage could fit the same PCB holes. The unidirectional polarity means the cathode band must be oriented correctly for the protected rail polarity.
Surge rating and clamping voltage for the BOM line
The 10.5 V clamping voltage at 143 A peak pulse current is the maximum voltage the downstream circuitry sees during a transient; a 5.8 V rail device rated for 10.5 V clamp means the protected ICs must survive at least that voltage for the pulse duration. The 'No Power Line Protection' flag confirms this part is not rated for continuous AC overvoltage — it is a transient suppressor, not a crowbar or circuit breaker.