Disclosed is a temperature sensor including a first current generator configured to generate a proportional to absolute temperature (PTAT) current, a second current generator configured to generate an inverse PTAT (IPTAT) current, the PTAT current and IPTAT current being combined to form a reference current having a sensitivity relative to temperature, a plurality of current mirrors to adjust the sensitivity and gain of the reference current, and a variable resistor to set an output calibration voltage based on the generated current.