Research And Design Of Low Noise Reference Circuit For High Speed A/D Converters

Reference module as an important module in integrated circuit,widely used in the mixed-signal circuits,such as A/D,D/A converters.With the development of high precision circuit system and the power supply reduced,the demanding of the reference and regulator in the module reference source are also increasing.Due to the traditional source of benchmark circuits has been unable to meet the application requirements,as also need to expand stabilizer of architecture in response to the output driving capability requirements of the reference in high precision systems which present a bigger challenge in temperature coefficient,the power supply rejection ratio and noise.First,in view of the temperature coefficient of traditional reference source is higher,the accuracy is lower,the output noise is bigger,and the insufficient power supply noise suppression capability,this paper proposes benchmark source based on a full CMOS custom point and the zero temperature coefficient(ZTC)point which supplemented by temperature curvature compensation technology and active damping circuit.This benchmark source has lower temperature coefficient and output noise,higher power supply noise suppression capability and higher accuracy.Second,because of the bigger noise,lower power inhibition,and the slow transient response,of the traditional linear regulators,it is not up to the application of high speed and high precision system.This paper proposes a class of linear regulator circuit based on Master-Slave architecture and the Slave local image unit in the system.This case greatly improves the driving ability of the buffers' output voltage as well as the transient response speed,and at the same time it is complementary with low noise design,reducing the noise of output voltage in high precision system new more.On the basis of the analysis,we design a kind of high precision and low noise reference circuit system according to the requirements of high speed time interweave SAR-ADC indicators,from the front end design verification to the backend layout design validation.The simulation results show that the temperature coefficient of the benchmark voltage source's output voltage is 6.68ppm/? in-40? to 125? temperature range,the power linear adjustment rate is 1.38ppm/V,the output voltage's power supply rejection ratio is 80 dB in the low frequency(10Hz),and the output noise of the benchmark voltage source's output is 38.49?V?The temperatue coefficient of the linear regulator's output voltage is under the 6ppm/?,and the output voltage's power supply rejection ratio is beyond the 30 dB,the summary output noise voltage is 140.107?V,and the simulation with the 12 bits high speed multi-channel ADC figures the ENOB as 11.88 bit effectively.The results of simulation show that the reference voltage circuit has reached the design requirements,figures the good performance and meet the application requirement of high speed multi-channels time-mixed ADC system.