3. Reference Voltage Buffer

Reference voltage is a ruler that is used by the ADC to weight the analog input. Accurate reference voltage plays an important role in the high-speed and high-resolution data conversion. In this chapter, we focus on the reference voltage buffer design. First, the traditional narrow-bandwidth buffer and wide-bandwidth buffer are depicted. The narrow-bandwidth one usually needs the large decoupling capacitors, which are difficult to be integrated on chip. The wide-bandwidth one normally consumes the large static current. Second, two reference buffers are introduced to exceed the limitations of the traditional designs. They are the level-shifter-aided reference buffer and the charge-compensation-based reference buffer. As a wide-bandwidth buffer, the level-shifter-aided reference buffer effectively saves the power dissipation. As a narrow-bandwidth buffer, the charge-compensation-based buffer does not need the large decoupling capacitors. At the end, we sum up the buffer designs for the low-power and high-performance ADC.