Device identity and surge rating
The SMBJ11A-13-F is a 600 W Zener TVS diode in the DO-214AA (SMB) package from Diodes Incorporated.
What the clamping specs mean for the rail
The 12.2 V minimum breakdown voltage is where avalanche conduction starts; the device is guaranteed to begin clamping above that threshold. For shorter pulses the device can absorb more peak power; for longer or repetitive surges the junction temperature rise must be derated per the datasheet's thermal impedance curve. The DO-214AA (SMB) surface-mount package has a standard footprint with a copper pad area under the cathode tab that sets the thermal resistance to the board. The Tape & Reel packaging is suited for automated pick-and-place assembly in volume production.