Breakdown and clamping window
The SMAJ170A-13: The minimum breakdown voltage is 189V, meaning the device starts conducting in avalanche mode once the rail rises above this threshold. The reverse standoff voltage of 170V is the maximum continuous DC voltage the TVS can withstand without significant leakage — a 170V bus or a 170V telecom line sits safely below the avalanche knee. The clamping voltage of 275V at 1.4A peak pulse current defines the protection ceiling: any transient that drives the line above 275V is clipped. The 400W peak pulse power (calculated as clamp voltage × peak current) confirms the device can absorb a single 10/1000µs surge up to that energy without failing short.
DO-214AC SMA footprint and thermal range
Housed in the DO-214AC (SMA) package, the SMAJ170A-13 is a surface-mount device with a standard JEDEC footprint.