In this project, a USB DAC was designed. This was done according to a proposal from Flexible Optical B.V. which is located in Rijswijk. This device is used to correct for atmospheric interference in optical measurement systems. The existing DAC is ten years old and needs to be updated to requirements of today. The 'next generation' DAC has been researched in-depth to see if the demanded requirements could be met. The design is divided into four subsystems: USB, controller, DAC, and power regulation and components have been chosen accordingly. Research showed that it was impossible to achieve the requested refresh rate with USB 2.0. The requirements were therefore altered to accommodate this shortcoming of USB 2.0, since a working prototype was more desirable than a faster product. The decision was then made to use a combo-unit that handles both the USB and the controller subsystem. For the DAC subsystem a single 40-channel DAC chip with a resolution of 16 bits was chosen. According to the needs of the other subsystems, a power regulation subsystem was designed. The entire system was first tested on a breadboard. This was used for prototyping and initial measurements. These measurement results did not fully comply with the requirements and adjustments had to be made. With these adjustments eventually all of the requirements have been fulfilled. To finalize the design and create a more stable and consistent design, a printed circuit board was designed and manufactured by Eurocircuits. However, it was not manufactured in time, and therefore no results regarding the printed circuit board are presented in this thesis. There are still some measurements that need to be done to ensure that all requirements are met. The printed circuit board design can still be improved upon to reduce distortion and increase its compactness. Furthermore, pick and place files should be made to make the manufacturing more efficient and other accommodating documents and files should still be finished for a final, market-ready product.