【作者】 朱慧珍；

【导师】 应建华；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2006， 硕士

【摘要】 数模转换器是数字电子系统和模拟电子系统之间的常用接口电路。在现代先进的电子系统前端和后端都要用到模数转换器和数模转换器,以改善数字处理技术的性能。在D/A转换器的众多转换网络中,梯形电阻网络在提高精度的同时,又节省了芯片的面积;同时电压型的梯形电阻网络可以实现输出电压与带隙电压同极性,因此得到了广泛的应用。本文设计了工作在4.5V-5.5V单电源电压下,12位高精度、低功耗的R-2R梯形电阻网络D/A转换器。由于输出运算放大器电路和带隙基准电路的性能对D/A转换器的性能影响很大,因此,本文主要研究运算放大器电路和带隙基准电路的设计。设计的运算放大器采用了两级结构放大,达到了109dB的开环放大倍数;带隙基准电路采用了指数型曲线补偿技术、反馈网络以及缓冲输出结构,达到了较低的温度系数、高的电源抑制比和较强的带负载能力。温度系数可以达到13.7ppm/℃;电源抑制比可达到163μV/V。仿真结果表明,设计的输出运算放大器和带隙基准电路满足12位D/A转换器的要求,该D/A转换器可以正常工作,积分非线性不超过0.5LSB,微分非线性不超过1LSB。更多还原

【Abstract】 The DAC is often used as the input/output circuit of digital electronic system and analog electronic system. In the front and the end of the advanced electronics system, digital to analog converters (D/A converters) are applied to improve the performance of the digital processing technique. Of all kinds of converter networks in D/A converters, the trapeziform resistor network not only advance the accuracy of the D/A converter but also save the area of the whole chip, the voltage type of the trapeziform resistor network is used widely for giving the output the same polarity as the input bandgap voltage.A 12-Bit high accuracy ,low power R-2R trapeziform resistor network D/A converter was designed, which operates from a single 4.5 to 5.5V power supply. Performances of output operational amplifier and the bandgap reference circuit have a very deep influence on the D/A converter, so the research of the two parts’design is focused on.The op amp with two stage circuit is designed, which can obtain 109dB open gain. For the design of the bandgap reference ,the architecture of exponential curvature-compensat- ed、the feedback circuit and the buffer output is employed, which satisfies the requirement of the low temperature coefficient and high power-supply rejection ratio and enhance the source and sink current. The TC is 13.7ppm/℃,and the psrr is 163μV/V.The simulation shows that the output op amp and the bandgap reference circuit meet the requirements of the 12-bit D/A converter, and the D/A converter can work well, the INL is not more than 0.5LSB, the DNL is not more than 1LSB.更多还原