0.8 High-speed Current-steering Dac Circuit Research And Design

A general introduction on Digital-Analog Converter study of domestic and aboard is presented. DAC principle and structures, and different converters such as current converting and voltage converting are analized.A 8-bit high speed DAC is designed. Based on the study of binary weighted DAC and thermometer-coded DAC, a thermometer-coded current-steering DAC is adopted. The principle, sub-circuit and layout of this DAC are also presented. The converter has the thermometer-coded architecture.This architecture implements the 8-bit DAC and achieves a good performance of dynamic character. This sample rate of this converter can be up to 500Msps. The SFDR and THD are up to 68dB and -61dB. The INL and DNL are smaller than 0.5LSB.The Structure of the converter is improved based on traditional one so that the area of glitch is reduced sharply and the dynamic character is improved.Some of the basic design theory and technology are presented. The basic cell architectures implemented in DAC are also presented. To improve the DAC, some of the cell architectures have to be designed carefully. The details of those cells are described. The actual circuit of current source, switch,bias and bandgap is presented.