12bit高稳定性数模转换器设计

设计了一款12 bit高稳定性控制类数模转换器(DAC),该DAC集成了带有稳定启动电路的新型低失调带隙基准源(BGR),改善了基准电路的稳定性以及对温度和工艺的敏感性;DAC采用了改进的两级电阻串结构,通过开关电阻匹配和特殊版图布局,在既不增加电路功耗又不扩大版图面积的前提下,提高了DAC的精度并降低了工艺浓度梯度对整体性能的影响.基于CSMC 0.5 μm 5 V 1P4M工艺对所设计的DAC芯片进行了流片验证.测试结果表明:常温下DAC的微分非线性(DNL)小于0.45 LSB,积分非线性(INL)小于1.5 LSB,并且在-55～125℃内DNL小于1 LSB,INL小于2.5 LSB;5V电源电压供电时功耗仅为3.5 mW,实现了高精度、高稳定性的设计目标.

Design of a 12 bit High-Stability Digital-to-Analog Converter

A 12 bit high-stability controlling digital-to-analog converter (DAC) was designed.By integrating a new low-offset bandgap reference (BGR) with stable start-up circuit,the DAC improved the stability of the reference circuit and the sensitivity to the temperature and process.An improved twostage resistor string structure was adopted by the DAC,which improved the accuracy of the DAC and reduced the influence of the process concentration gradient on the overall performance without increasing the circuit power consumption and expanding the chip area through the switch resistance matching and special layout.Based on the CSMC 0.5 μm 5 V 1P4M process,the designed DAC chip was verified.The test results show that the differential nonlinearity (DNL) of the DAC at room temperature is less than 0.45 LSB and the integral nonlinearity (INL) is less than 1.5 LSB.Moreover,the DNL in the temperature range of-55 ℃ to 125 ℃ is less than 1 LSB and the INL is less than 2.5 LSB.The power consumption of the 5 V supply voltage is 3.5 mW,achieving the design objectives of high precision and high stability.