An temperature sensor circuit is disclosed. In one embodiment, the temperature sensor comprises an input circuit with a current mirror for forcing a current down a reference stage and an output stage. The reference stage and the output stage include P-N junctions (e.g., using bipolar transistors) with differing junction potentials. By tailoring the resistances in the reference and output stages, the input circuit produces two output voltages, one of which varies predictably with temperature, and one which is stable with temperature. The input circuit is preferably used in conjunction with an amplifier stage which preferably receives both the temperature-sensitive and non-temperature-sensitive outputs. Through various resistor configurations in the amplifier stage, the output of the temperature sensor can be made to vary at a higher sensitivity than produced by the temperature-sensitive output of the input circuit. Moreover, as a result of the non-temperature-sensitive output, the output of the temperature sensor is additionally and beneficially tailored in its offset voltage in a temperature-independent manner. The result is a flexible circuit that can achieve very high sensitivities and near-ideal performance even at lower power supply voltages.