What this TVS diode protects and how it clamps
The reverse standoff voltage is 29.7V — the rail voltage must stay below this level for the diode to remain non-conducting. Above that, breakdown begins at 37.1V min, and the clamping voltage peaks at 53.6V under full surge current. That 53.6V ceiling is what the protected circuit must survive without damage. With a peak pulse current rating of 28A, the device can handle substantial surge events typical of lightning-induced transients or inductive load switching.
Housed in a SQ-MELF (C) surface-mount package, the 1N6156US/TR offers a low-inductance path for fast transients and good solder-joint reliability under thermal cycling.