Abstract
In this research, we describe the design and characterization of a 8×8 and a 16×16 temperature sensor arrays implemented in a standard CMOS process. The presented construction is based on PMOS transistors operated in saturation region for thermal sensing. Its output level is determined by the sensing PMOS transistor’s saturation current which is proportional to temperature. For the 8×8 sensor array the sensing transistors are placed in the chip center with local polysilicon heaters, preventing other transistors of the sensing circuit from being affected by the temperature variation in the sensors’ area and obtain a more dense arrangement of the sensor array. Also in the 8×8 array, the biasing circuits are shared by every 8 cells, so the chip area could be reduced. In the 16×16 array, all the 256 sensors share one biasing circuit, so the chip area and the power consumption could be more reduced. The 8×8 sensors have an area of 202 μm by 183 μm whereas the 16×16 sensors have an area of 513 μm by 777 μm. The measured resolution is about 5 mV/1℃, whereas the minimum resolution could achieve 0.1℃. The presented temperature sensing could operate accurately over the temperature range 25℃~40℃ with a deviation of 8.73%.