Electronic field device

An apparatus for determining and/or monitoring at least one process variable of a medium in a containment, the apparatus comprising:

• at least one sensor unit;
• and
• an electronics unit that includes a transceiver unit and a transceiver protecting unit configured to limit an input voltage of the transceiver unit to a first transceiver voltage value, wherein:
• the transceiver protecting unit includes a first limiting unit and a transistor unit having at least one transistor;
• the transistor unit is connected in series with the transceiver unit;
• the first limiting unit is connected in parallel with transceiver unit and to a control terminal of the transistor;
• and
• the first limiting unit is configured to control an input voltage of the control terminal of the transistor to a predeterminable control value such that the input voltage of the transceiver unit is limited to the first transceiver voltage value when a supply voltage to the electronics unit exceeds a limit value.