ABSTRACT
Real-world analog signals such as temperature, pressure, sound, or images are routinely converted to a digital representation that can be easily processed in modern digital systems. In many systems, this digital information must be converted back to an analog form to perform some real-world function. The circuits that perform this step are digital-to-analog converters (DACs), and their outputs are used to drive a variety of devices. Segmented architectures, where the full resolution of the converter is spread across two or more sub-DACs, can be used for both current- and voltage-output DACs. The R–2R architecture can be used as a voltage- or current-mode DAC. A delta–sigma architecture can be used for DACs where linearity is preferred over bandwidth. Architecture is not the sole contributor to DAC performance. DACs are made up from a combination of switches, resistors, amplifiers, and logic. Building a monolithic DAC in a bipolar process can provide good device matching, which yields good direct current (DC) performance.
