The Design Of Industrial-grade 16 Current Steering Dac

Data converters, i.e., analog-to-digital converters (ADCs) and digital-to-analog converters (DACs), are interface circuits between the analog and digital domains. As the continuous improvement of industrial control system on accuracy and speed, the accuracy and speed of data converters have become main restricting factors in the entire industrial control systems. Although dynamic performances of DAC are considered in the first place for communications applications, static performances of DAC are much more critical in industrial applications. The DAC architecture considered in this work is the current-steering DAC, which is the most commonly used architecture for high-speed applications. Since there huge mismatch between MOSFET in integrated circuit fabrication process, the limit of accuracy of the current-steering DAC is generally10-bit which obviously cannot meet the requirement of a16-bit DAC.To solve the above problem, the error sources in current-steering architecture are analyzed in this work; the impacts of different digital encoding methods and different transistors’ gate-area on DAC performance are discussed. By applying self-calibration technique, a new16-bit segmented current-steering DAC is presented. A bandgap voltage reference which can be used in16-bit DAC is also presented in this work.The DAC and the bandgap reference are designed and simulated in HHNEC BCD35process. The differential nonlinearity (DNL) and integral nonlinearity (INL) of the DAC are0.25and0.3least significant bits (LSB’s), respectively; the setting time of the DAC is less than40ns. The temperature coefficient over the industrial temperature range is3.1ppm/℃. The results show that the design in this work can meet the requirements of industrial applications.