Its 170V reverse standoff voltage makes it a fit for 120VAC or 170VDC rail protection in industrial power supplies, telecom rectifiers, and automotive battery lines where transient surges from load dump or lightning coupling are a concern. The device clamps at 304V maximum at the rated 4.9A peak pulse current, providing a defined voltage ceiling for downstream semiconductors. The wide operating junction temperature range from -65°C to 150°C supports deployment in engine compartments, outdoor enclosures, and other thermally demanding environments.
For a 170V rail, the 304V clamping voltage gives a 134V headroom above the standoff, which is typical for a Zener TVS at this voltage class. The 4.9A peak pulse current is the corresponding current the device can sink at the clamp voltage. Unidirectional construction means the cathode must be oriented to the protected rail, anode to ground. This part is not intended for AC line protection where bidirectional clamping is needed — the Power Line Protection field is marked No.
The base product number SMCJ170 covers the full family; the /TR13 suffix should be matched exactly for the tape-and-reel variant.