500W Zener TVS in a hermetic SQ-MELF
The SQ-MELF B package is a hermetic, surface-mount ceramic barrel — the same footprint used in MIL-spec and high-reliability designs where epoxy-molded parts risk moisture ingress or thermal cycling fatigue.
Clamping voltage and pulse current — the real protection numbers
That means a 5V rail sees the diode clamp at roughly double the nominal voltage during a surge — enough to keep downstream 5V-rated ICs inside their absolute-maximum ratings if the PCB layout keeps trace inductance low.
The base product number is 1N6103, so variants with different screening levels or lead finishes share the same die.