A reference voltage in capacitor–resister hybrid SAR ADC for front-end readout system of CZT detector

【摘要】 An on-chip reference voltage has been designed in capacitor–resister hybrid SAR ADC for CZT detector with the TSMC 0.35μm 2P4M CMOS process.The voltage reference has a dynamic load since using variable capacitors and resistances,which need a large driving ability to deal with the current related to the time and sampling rate.Most of the previous articles about the reference for ADC present only the bandgap part for a low temperature coefficient and high PSRR.However,it is not enough and overall,it needs to consider the output driving ability.The proposed voltage reference is realized by the band-gap reference,voltage generator and output buffer.Apart from a low temperature coefficient and high PSRR,it has the features of a large driving ability and low power consumption.What is more,for CZT detectors application in space,a radiation-hardened design has been considered.The measurement results show that the output reference voltage of the buffer is 4.096 V.When the temperature varied from 0 to 80℃,the temperature coefficient is 12.2 ppm/℃.The PSRR was 70 d B@100 k Hz.The drive current of the reference can reach up to 10 m A.The area of the voltage reference in the SAR ADC chip is only 449614 m~2.The total power consumption is only 1.092 m W.更多还原

【Abstract】 An on-chip reference voltage has been designed in capacitor-resister hybrid SAR ADC for CZT detector with the TSMC 0.35 μm 2P4 M CMOS process.The voltage reference has a dynamic load since using variable capacitors and resistances,which need a large driving ability to deal with the current related to the time and sampling rate.Most of the previous articles about the reference for ADC present only the bandgap part for a low temperature coefficient and high PSRR.However,it is not enough and overall,it needs to consider the output driving ability.The proposed voltage reference is realized by the band-gap reference,voltage generator and output buffer.Apart from a low temperature coefficient and high PSRR,it has the features of a large driving ability and low power consumption.What is more,for CZT detectors application in space,a radiation-hardened design has been considered.The measurement results show that the output reference voltage of the buffer is 4.096 V.When the temperature varied from 0 to 80℃,the temperature coefficient is 12.2 ppm/℃.The PSRR was-70 dB@ 100 kHz.The drive current of the reference can reach up to 10 mA.The area of the voltage reference in the SAR ADC chip is only 449× 614 μm~2.The total power consumption is only 1.092 mW.更多还原