A Fully CMOS-Compatible Micro-Pirani Gauge based on a Constant Current

The paper presents a CMOS-compatible micro-Pirani sensor which consists of the tungsten micro-hotplate and the constant current circuit based on the operational amplifier. The advantage of the constant current circuit for the micro-Pirani sensor is that it is more sensitive than the constant temperature one in the low gas pressure. The micro-Pirani system is implemented in an industrial 0.5-mum CMOS process. The measurement results show that the designed micro-Pirani sensor has a good response to the gas pressure, especially in the low gas pressure ranging from 1 Pa to 100 Pa, the sensitivity of the sensor is 0.23 mV/Pa and the linearity is 4.95%.