一种16位电流舵DAC的高精度前台校准方法

A high Precision Foreground Calibration Technique for 16 Bit Current Steering DAC

基于28 nm CMOS工艺,采用一种高精度的前台校准技术设计了一款16 bit电流舵数模转换器(Digitalto-analog converter,DAC)电路。该前台校准算法对16 bit数据对应的所有电流源进行校准,并且使用的电流源只有两种大小,降低校准难度的同时也提升了校准的精度。该校准电路引入了两种校准补充电流,分别用于温度和输出电流变化引起电流源失配的补偿,进一步减小了DAC电流源的失配,有效提高了DAC的整体性能。采用校准后,在-40~85℃温度范围内,微分非线性≤0.8 LSB,积分非线性≤2.0 LSB,200 MHz输出信号下无杂散动态范围≥75.3 dB。该校准方法提高了DAC的温度稳定性。

This paper is devoted to the high-precision foreground calibration circuit for 16 bit cur-rent-steering digital-to-analog converter(DAC)using 28 nm CMOS technology.All current sources of the digital-to-analog converter were calibrated with a calibration circuit,and only two sizes of cur-rent sources were used for the digital-to-analog,which reduced the difficulty of calibration and im-proved the accuracy of calibration.The calibration circuit introduced two kinds of calibration compen-sation currents,which were used for current source mismatch compensation due to temperature and output current variation,respectively.The calibration scheme could effectively reduce the current source mismatch and improve the overall performance of DAC.After calibration,the differential non-linearity is below 0.8 LSB,the integral nonlinearity is below 2.0 LSB and the spurious free dynamic range is above 75.3 dB for 200 MHz output signal in the range of-40℃to 85℃.This calibration scheme improves temperature stability of DAC.