A sensor device includes an implantable sensor unit, a transponder unit, and a wired connection flexibly and electrically connecting the implantable sensor unit and the transponder unit. The implantable sensor unit is adapted to be implanted into a body. The implantable sensor unit includes a comparator and a sensor adapted to sense a characteristic of the body in vivo. The sensor is adapted to supply an analogue signal to a first input of the comparator. The transponder unit is adapted to supply a control signal to the implantable sensor unit and to receive an output signal of the comparator. The implantable sensor unit is adapted to supply an analogue approximation signal to a second input of the comparator in response to the control signal. The wired connection is adapted to transmit the control signal and the output signal of the comparator.
