Integrated temperature sensor for measuring temperature, comprising: - oscillator means for generating from a pulse (OSC_ENABLE) a pulse train (DATA_IN) at a certain oscillation frequency which is dependent on the temperature to be measured, wherein said pulse (OSC_ENABLE) is generated from at least one reference signal independent of the temperature to be measured, said at least one reference signal being extractable from an external signal from a reader, the width of said pulse (OSC_ENABLE) from which the pulse train (DATA_IN) is generated determines the time during which said pulse train (DATA_IN) is generated; said oscillator means for generating a pulse train (DATA_IN) comprising a plurality of logic gates (2410, 2420, 2430, 2440, 2450) which are capable of introducing a delay dependent on the temperature to be measured; - one binary counter block for counting the number of pulses of said pulse train (DATA_IN) during a fixed time independent of the temperature to be measured and for generating a plurality of bits (b11, b10,..., b0) indicating the number of pulses comprised in the pulse train (DATA_IN), said one binary counter block counting said number of pulses from the following input signals: the pulse train (DATA_IN) generated by said oscillator means, a pulse (TEMP_MEAS) whose width determines the time, independent from the temperature to be measured, during which the pulses which form said pulse train (DATA_IN) are counted, and a pulse (ENABLE) whose width defines the time during which the sensor operates, said input signals (DATA_IN, TEMP_MEAS, ENABLE) being obtainable from said at least one reference signal independent of the temperature to be measured and from a step signal (START) used to initiate the measurement process of the sensor, said binary counter block providing a binary digital representation of the temperature measurement; - means for generating a serial digital signal (DATA OUT, DATA_OUT@T) from said plurality of bits (b11, b10,..., b0), said serial digital signal (DATA_OUT, DATA_OUT@T) representing a measured temperature. - oscillator means for generating from a pulse (OSC_ENABLE) a pulse train (DATA_IN) at a certain oscillation frequency which is dependent on the temperature to be measured, wherein said pulse (OSC_ENABLE) is generated from at least one reference signal independent of the temperature to be measured, said at least one reference signal being extractable from an external signal from a reader, the width of said pulse (OSC_ENABLE) from which the pulse train (DATA_IN) is generated determines the time during which said pulse train (DATA_IN) is generated; said oscillator means for generating a pulse train (DATA_IN) comprising a plurality of logic gates (2410, 2420, 2430, 2440, 2450) which are capable of introducing a delay dependent on the temperature to be measured; - one binary counter block for counting the number of pulses of said pulse train (DATA_IN) during a fixed time independent of the temperature to be measured and for generating a plurality of bits (b11, b10,..., b0) indicating the number of pulses comprised in the pulse train (DATA_IN), said one binary counter block counting said number of pulses from the following input signals: the pulse train (DATA_IN) generated by said oscillator means, a pulse (TEMP_MEAS) whose width determines the time, independent from the temperature to be measured, during which the pulses which form said pulse train (DATA_IN) are counted, and a pulse (ENABLE) whose width defines the time during which the sensor operates, said input signals (DATA_IN, TEMP_MEAS, ENABLE) being obtainable from said at least one reference signal independent of the temperature to be measured and from a step signal (START) used to initiate the measurement process of the sensor, said binary counter block providing a binary digital representation of the temperature measurement; - means for generating a serial digital signal (DATA OUT, DATA_OUT@T) from said plurality of bits (b11, b10,..., b0), said serial digital signal (DATA_OUT, DATA_OUT@T) representing a measured temperature.