The Study And Design Of CMOS Bandgap Reference Based On40nm Technology

Bandgap Reference source is an important module in the analog circuit, which is widelyused in many circuits, such as ADC, DAC, LDO and other analog or mixed circuits; itsperformance directly affects the accuracy of the system. In recent years, the power voltage hasbeen reduced with the decreasing of the characteristic size in IC, and the demand to thereference is more and more high. As a result, it is very important to research the CMOSbandgap reference.The thesis designs a bandgap reference source on the basis of the TSMC40G CMOSprocess and the circuits are simulated and verified with spectre. Because of the current-modearchitecture, the reference output voltage does not have a limitation of1.25V, which couldchange as required. First, the bandgap reference source which uses a single operationamplifier with the folded-cascode architecture is implemented with first-order temperaturecompensation. The temperature coefficient of the reference output voltage is14ppm/°C in thetemperature range from-40°C to125°C, and PSRR is-61dB in the low frequency. Because ofthe weakness PSRR of the bandgap reference source with a single folded-cascode operationamplifier, the bandgap reference source with two-stage folded-cascode operation amplifier isdesigned and its PSRR can achieve to-81dB. Afterwards, the bandgap reference source iscompensated in the high order compensation technology of linearization for V_BE thetemperature coefficient can reach2.6ppm/°C, and PSRR is-101dB for the bandgap referencesource after adding to the subtracter. The layout of bandgap reference source is successfullydesigned on the basis of taking the impacts into account during the layout design, which isverified by DRC and LVS. The post-simulation is accomplished and the simulation resultshows that the circuit achieves design specification. In order to improve the accuracy, thebandgap reference with the technology of chopper stabilization is designed, and thesimulation result shows that the accuracy is raised by76times.