Zener voltage and tolerance — the BOM-fit numbers
The 1N6031C is a 200 V Zener diode with a ±2% tolerance. That tight tolerance means the actual breakdown voltage sits between 196 V and 204 V — narrow enough to use as a precision voltage reference or a clamp in a 200 V rail without trimming. The 500 mW power dissipation ceiling limits the steady-state current to about 2.5 mA at the nominal voltage; for higher current the junction temperature rise at 175 °C max must be checked against the derating curve.
Reverse leakage and forward drop — guardband considerations
Reverse leakage is specified at 100 nA maximum when tested at 152 V reverse bias. That is 76 % of the nominal breakdown voltage, so the leakage current stays in the nanoamp range until the diode enters avalanche — important for high-impedance bias circuits where leakage shifts the operating point. Forward voltage is 1.1 V maximum at 200 mA forward current, typical for a silicon Zener of this voltage class.
Supplied in a DO-204AH (DO-35) axial-lead glass package. Bulk packaging means loose tubes or bags, not tape-and-reel; factor this into the pick-and-place process if automated insertion is planned.