一种具有微处理器接口的CMOS 12位电流型D/A转换器

A 12 Bit CMOS Current Mode Digital to Analog Converter Using Segmented Ladder Networks

研究了采用译码的分段梯形电阻网络技术制作的高速１２位ＣＭＯＳ电流型Ｄ／Ａ转换器。将常规的Ｒ－２Ｒ电阻网络和译码的权电阻网络相结合，解决了常规ＣＭＯＳＤ／Ａ转换器必须采用精密Ｒ－２Ｒ梯形电阻网络的问题，降低了对电阻精度匹配的要求。同时，为了使Ｄ／Ａ转换器具有灵活的外围应用，专门设计了微处理器接口、基准发生器和量程选择电阻。未修调的实验样品的线性误差小于０．０５％，建立时间为４００ｎｓ。

A high speed 12 bit CMOS current mode digital to analog converter based on segmented resistor ladder networks for decoding has been developed Combined with R 2R resistor ladder and weighted resistor networks for decoding, it eliminates the need for a precise R 2R ladder network that is necessary for a conventional CMOS D/A converter It also lowers the requirement for match of resistor’s accuracy An interface to microprocessor, reference generators and resistors for range selection are designed to make the D/A converter more flexible in peripheral applications For the sample circuit without trimming, a linear error less than 0 05% and a settling time of 400 ns have been obtained