What the 1500W peak pulse rating means for your protection design
The 1.5SMB68A is a 1500W (1.5kW) peak pulse power TVS diode from Littelfuse's 1.5SMB series, designed to clamp transients on telecom and industrial DC rails. For a 58.1V reverse standoff voltage (the DC rail it protects without conducting), the 64.6V minimum breakdown ensures the avalanche region is entered only when the transient exceeds the normal operating voltage. The 118.9V clamping ceiling limits the spike seen by the downstream circuitry.
Package and board-fit for the DO-214AA SMB
Housed in the DO-214AA (SMB) package, the 1.5SMB68A is a surface-mount device that reflows alongside standard passive components. The supplier device package is also listed as DO-214AA (SMBJ), so the footprint is consistent across the 1.5SMB family. Operating temperature spans -65°C to 150°C junction, covering the full telecom ambient range with margin. It is a unidirectional Zener TVS — one channel, cathode banded — suitable for positive-rail clamping where the transient polarity is known. Power line protection is not supported (the diode is not bidirectional), so for AC signal lines or bipolar rails a bidirectional variant from the same series would be needed.
Active lifecycle and sourcing posture
The base product number 1.5SMB covers the full family, so the 68A variant remains a standard catalogue item.