A 0.001mm² 100µW on-chip temperature sensor with ±1.95 °C (3σ) Inaccuracy in 32nm SOI CMOS

We report an on-chip temperature sensor that uses the temperature-dependent reverse bias leakage current of a lateral SOI-CMOS pn diode to measure the thermal profile of a 32-nm microprocessor core. In this system, the diode junction capacitance is first charged to a fixed voltage. Subsequently, the diode capacitance is allowed to self-discharge by its reverse bias leakage current to create a temperature-dependent time pulse whose width is measured by a digital counter. This sensor demonstrates a 3s measurement inaccuracy of ±1.95 °C across the 5-100 °C temperature range while consuming 100 μW from a single 1.65 V supply.