The 1N6335US is a 30 V Zener diode rated for 500 mW continuous power dissipation in a hermetic SQ-MELF B surface-mount package. The 30 V nominal breakdown (Vz) sets the regulation or clamping threshold; the 500 mW ceiling means the diode can sink about 16.7 mA at 30 V before the junction temperature drives derating. In a voltage-reference circuit drawing 5 mA, the 500 Ohm max Zener impedance (Zzt) contributes 2.5 V of line-regulation error — tight enough for a 5% rail but not for a precision bandgap substitute.
Temperature grade and package — where this diode fits
The -65°C to 175°C operating range puts this part in the military/aerospace and downhole temperature band — the hermetic SQ-MELF B package (ceramic body with metallized end caps) seals the die against moisture and thermal cycling that would crack a plastic SOD-123. Reverse leakage is only 50 nA at 23 V (Vr), so standby dissipation in a battery-powered voltage monitor stays under 1.15 µW. The 1.4 V forward drop at 1 A (Vf) confirms it can handle brief reverse-polarity transients without damage, though the 500 mW power limit governs continuous forward current.