400W bidirectional TVS in the SMA footprint
It is designed for general-purpose overvoltage protection, clamping transients on power rails and signal lines where the normal operating voltage is 18 V. The part is rated for a peak pulse power of 400 W, with a breakdown voltage range starting at 20 V and a maximum clamping voltage of 39.3 V at the peak pulse current of 59 A (8/20 µs waveform).
The 39.3 V clamping voltage at 59 A (8/20 µs) tells you the maximum voltage the protected circuit will see during a surge. For a 12 V supply rail, the 18 V standoff provides headroom without leakage; the 20 V breakdown ensures the device starts conducting before the rail exceeds safe limits. The 400 W peak pulse power defines the energy the part can absorb in a single pulse — sufficient for ESD and inductive-load transients, but for higher-energy events (e.g., lightning surge on exposed cables) a larger package like the SMBJ series may be needed.
Package and board-level integration
The DO-214AC (SMA) package is a widely used footprint for TVS diodes, compatible with standard reflow soldering profiles. No power line protection is provided internally — this is a transient clamp, not a regulator. The bidirectional configuration means a single device protects both positive and negative transients on a line, simplifying BOM count for AC-coupled or bipolar signal paths.