Design And Research Of High-resolution Sigma-delta A/D Converter

Demands for the reliability of electronic devices have been put forward with the rapid development of aerospace technology.Radiation damage in space is one of the main factors for the failure of electronic devices.Major issues related to the design of high-performance Sigma-Delta ADC and radiation-harden methods are discussed in this thesis.Particular attention should be given to the following three aspects:A 16bit radiation-hardened Sigma-Delta modulator.To obtain more accurate model,a non-ideal system model is built using MATLAB.The single loop feed-forward fourth order modulator achieved 16.89 bits.The circuit design and layout drawing were performed by using 0.18?m SOI process.Main circuits include:operational amplifier,switched capacitor integrator,adder,quantizer,clock generation circuit and clock buffer.The layout area is 550?m×845?m.Post-simulation showed that,the noise floor is-116dB,at the bandwidth of 2kHz,ENOB reaches 16.31bits,dynamic range is more than 100dB,all of which satisfy the design specifications.Two radiation-harden bandgap circuits.One is using a proportion voltage of the triode emitter voltage and output voltage to eliminate the deviation caused by the leakage current of the transistor.The other way to stabilize the output is by employing NPN triode to absorb the leakage current of the PNP triode.Both of the two methods have good radiation-harden performance and are verified by avant simulation.The Sigma-Delta digital decimation filter.The digital decimation filter is divided into 4 stages:CIC filter,CIC compensation filter,first level half band filter and second level half band filter.And the multiplier in the FIR filter is improved by the Booth algorithm multiplier so as to reduce the requirement of system clock.Finally,the simulation verification showed that it can achieve better down-sampling and filtering results.