6.8 V Zener in a hermetic SQ-MELF
The 1N6320US/TR is a 6.8 V Zener diode rated for 500 mW continuous power dissipation in a hermetic SQ-MELF (B) package. The ±5% tolerance on the nominal voltage is the standard grade for general-purpose voltage clamping and shunt regulation — the actual Vz at the test current will fall between 6.46 V and 7.14 V. A maximum Zener impedance of 3 Ohms means the regulation stiffness is tight at the specified test current — the dynamic resistance is low enough that the output voltage shifts only modestly with changes in bias current, which matters when the diode is used as a reference for a comparator or as a clamp on a supply rail.
Temperature range and leakage
The operating junction temperature spans -65°C to 175°C, a military-grade range that suits avionics, downhole instrumentation, and satellite power supplies where the ambient extremes exceed commercial or industrial limits. Reverse leakage is specified at 2 µA maximum at 4 V reverse bias — roughly 60% of the nominal Zener voltage. This low leakage keeps standby power draw negligible in battery-backed circuits and confirms the junction quality at the lower end of the operating temperature range.
The SQ-MELF (B) package is a hermetic surface-mount form factor — the ceramic body and metal lid seal the die against moisture and corrosive atmospheres, making it a common choice for high-reliability and military/aerospace assemblies where plastic packages are not accepted. The B suffix denotes the specific outline; the supplier device package is listed as B, SQ-MELF. Supplied in Tape & Reel (TR) for automated pick-and-place assembly. The forward voltage is specified at 1.4 V maximum at 1 A forward current — this is the conduction drop if the diode is forward-biased, not the Zener regulation mode.