Low capacitance silicon controlled rectifier (SCR) topologies for overvoltage protection are disclosed herein. In certain embodiments, an overvoltage protection circuit is connected between an RF signal pad and a ground signal pad. The overvoltage protection circuit includes a fin field-effect transistor (FinFET) SCR including a PNP bipolar transistor and an NPN bipolar transistor that are cross-coupled, a FinFET trigger circuit connected between an emitter of the PNP bipolar transistor and a base of the NPN bipolar transistor, and a linearity enhancement impedance connected between a reference voltage terminal and the emitter of the PNP bipolar transistor. In certain implementations, a FinFET diode is further included in series with the FinFET SCR with a cathode of the FinFET diode connected to the emitter of the PNP bipolar transistor.

A module (100) is specified, the module (100) comprising a first module connection (108), a second module connection (109), an energy store (105), a first electrical switch (101) and a second electrical switch (102), wherein a switchable bypass device (1) is arranged between the first module connection (108) and the second module connection (109) and wherein the switchable bypass device (1) is configured to remain in a bidirectional current conducting state in response to a single trigger pulse.