This master's thesis presents the design, implementation and characterisation of a 12-bit current digital-to-analog converter for use in an application-specific integrated circuit. The converter is designed in 180 nm CMOS process and must fulfill requirements regarding monotonicity, differential nonolinearity, output current and operation across a range of supply voltage, temperature and process variations. A special requirement of the end application is the use of the same converter in 12-bit mode with single-ended output and 10-bit mode with differential output. In the beginning various architectures and their benefits and drawbacks are presented. Afterwards the chosen segmented architecture with current divider, which enables guaranteed monotonicity at low power and small area consumption is presented. Special consideration is given to the current divider design, where dcMatch analysis was used to analyze the relation between transistor matching and their dimensions. A configuration which allows for 8-bit resolution at a small area, was chosen on the basis of this analysis. The whole circuit is then presented and its operation is explained. The converter's operation is then tested with simulations and measurements on a produced integrated circuit. The achieved results confirm that the converter fulfills all requirements and is suitable for use in the target application.
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