用于BAN的自校准SAR ADC设计

Design of a SAR ADC with Self-Calibration for BAN

基于SMIC 0.18μm CMOS混合信号工艺,设计了一种适用于体局域网(BAN)的自校准逐次逼近型模数转换器(SAR ADC)。基于BAN系统的特点,设计的SAR ADC采用阻容混合型主数模转换器(DAC)及电容型校准DAC等结构。采用误差自校准技术来校准SAR ADC的阻容混合型主DAC的高5位电容失配误差,有效降低了SAR ADC非线性误差。仿真结果表明,自校准SAR ADC获得了±0.3LSB微分非线性、±1LSB积分非线性、82.2dB信噪比等性能特性。设计的SAR ADC具有良好的性能,适合于BAN系统。

A successive approximation register（SAR）analog-to-digital converter（ADC）was designed for body area network（BAN）in the SMIC 0.18μm CMOS mixed-signal process.Based on the characteristics of BAN system,the resistor-capacitor（R-C）hybrid master digital-to-analog converter（DAC）and the capacitance calibration DAC were adopted.An error self-calibration technique was used to calibrate the high 5-bits capacitor mismatch errors of the R-Chybrid master DAC,and the nonlinear errors of the SAR ADC was reduced effectively.Simulation results showed that the proposed self-calibration SAR ADC had achieved performances of ±0.3 LSB differential nonlinearity（DNL）,±1 LSB integral nonlinearity（INL）and 82.2 dB signal to noise ratio（SNR）.The self-calibration SAR ADC had nice performances and was suitable for the BAN system.