The TBU® High-Speed Protector is a silicon-based, solid-state, resettable device which is placed in series with a signal path. The TBU® HSP operates in approximately 1 µs, once line current exceeds the TBU® HSP trigger current ITRIGGER.  When operated, the TBU® HSP restricts line current to less than 1 mA, typically and will block all system voltages and any other voltages including the surge up to rated limits. After the surge, the TBU® HSP resets when the voltage across the TBU® HSP falls to the VRESET level. The TBU® HSP will automatically reset on lines that have no DC bias or have DC bias below VRESET (such as unpowered signal lines). If the line has a normal DC bias above VRESET, the voltage across the TBU® HSP may not fall below VRESET after the surge. In such cases, special care needs to be taken to ensure that the TBU® HSP will reset, otherwise an automatic or manual power down will be required.