A sensor device (10) comprises an implantable sensor unit (100), a transponder unit (200), and a wired connection (300) flexibly and electrically connecting the implantable sensor unit (100) and the transponder unit (200). The implantable sensor unit (100) is adapted to be implanted into a body. The implantable sensor unit (100) comprises a comparator (120) 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 (120a) of the comparator (120). The transponder unit (200) is adapted to supply a control signal to the implantable sensor unit (100) and to receive an output signal of the comparator (120). The implantable sensor unit (100) is adapted to supply an analogue approximation signal to a second input (120b) of the comparator (120) in response to the control signal. The wired connection (300) is adapted to transmit the control signal and the output signal of the comparator (120).
