Clamping voltage and the protection window
The SMAJ120A-13: When it does fire, the clamping voltage holds at 193 V maximum at the 2 A peak pulse current (10/1000 µs waveform). That 193 V ceiling is the number that matters for downstream silicon — if the bus voltage never exceeds 120 V in normal operation, the 133 V breakdown gives enough margin to avoid nuisance triggering from normal line ripple or switching noise.
DO-214AC SMA footprint and board integration
Housed in the standard DO-214AC (SMA) package, this TVS mounts directly on the PCB with a surface-mount reflow profile compatible with lead-free soldering. The SMA footprint is shared across the wider SMAJ family, so a single board layout can accommodate different voltage variants by populating the appropriate order code.
Sourcing and compliance
The SMAJ120A-13 is a general-purpose TVS diode with no integrated power-line protection features — it is designed for signal and low-power rail clamping, not for mains or high-energy surge suppression. RoHS compliance is standard for the Diodes Incorporated SMAJ series.