Research And Design On CMOS Operation Amplifier Circuit In High Temperature Based On Aluminum Gate Process

In recent years, with the constant improvement of the level of science and technology,and rapid development of the industrial production capacity, integrated circuit is used moreand more widely. In some special fields, temperature for integrated circuit is higher andhigher, and the working environment of integrated circuit temperature also has higherrequirements, so the high temperature resistant integrated circuit design technology isbecoming a research hotspot. As the temperature of the working environment constantly rises,offset voltage of CMOS operational amplifier also increases.When the environmenttemperature exceeds150℃, the main composition of p-n junction’s leakage current changesto inverse diffusion current which increases dramatically as the temperature rises. The valueis relatively large in high temperature, thus, CMOS operational amplifier’s characteristics ofdc and ac deteriorate, resulting in abnormal working of CMOS operational amplifier in hightemperature environment.This dissertation does a wide range of investigation and research on the technology ofhigh temperature analog circuit at home and abroad, studies and analyzes the base model,working principle and advantages and disadvantages of these technologies, and combinestheoretical analysis with technological achievement, thus, according to the design rules ofhigh temperature analog circuit, designing a secondary CMOS analog operational amplifierwhich can work normally under200℃environment temperature.To realize strong anti-interference ability of the circuit and reduce its offset voltage andtemperature-drift, differential amplifier is used to realize the input stage of high temperatureCMOS op amp; intermediate stage is also gain stage which adopts wide-swing cascodearchitecture; In order to ensure the stable working state of CMOS operational amplifier in thehigh temperature, the circuit is required to work at zero temperature coefficient, so the designof the bias circuit is particularly important; In order to improve the circuit load capability andensure low output impedance and good frequency response characteristics, source followeris used as output stage, and miller compensation is adopted for the frequency compensation ofoperational amplifier.A layout design for this electric circuit is made according to the layout design rulesprovided by a domestic flow sheet manufacturer, the Spectre simulation tools is adopted forthe detailed simulation of the designed circuit, and the flow sheet and related tests arecompleted in this flow manufacturer. Under the conditions of single power supply voltage ofenvironment temperature being200℃, VCC=5V, VEE=0V, the test results show that thedc open-loop gain reaches80db, the phase margin55degrees, typical value of unit gain bandwidth1.5MHZ, offset voltage0.8mv, and temperature-drift3μ v/C. The varioustechnical indexes reach the expected design requirements.The designed operational amplifier can be used in the system equipment of oilexploration, aerospace and other related fields.