12-bitni tokovni D/A pretvornik z diferencialnim izhodom

TOŠKAN, VILJEM (author), Strle, Drago (mentor)

V magistrskem delu je predstavljena zasnova, izvedba in karakterizacija 12-bitnega tokovnega digitalno-analognega pretvornika, namenjenega uporabi v namenskem integriranem vezju. Pretvornik je načrtovan v 180 nm CMOS tehnologiji in mora izpolnjevati zahteve glede monotonosti, diferencialne nelinearnosti, izhodnega toka ter delovanja v širokem območju napajalnih napetosti, temperatur in procesnih variacij. Posebna zahteva aplikacije je uporaba istega pretvornika tako v 12-bitnem načinu z enojnim izhodom kot tudi v 10-bitnem načinu z diferencialnim izhodom. Na začetku so predstavljene različne arhitekture D/A pretvornikov ter njihove prednosti in slabosti glede na podane zahteve. Nato je predstavljena izbrana segmentirana arhitektura s tokovnimi viri in tokovnim delilnikom, ki omogoča zagotovljeno monotonost ob hkrati razmeroma majhni porabi in površini. V nadaljevanju je opisan postopek načrtovanja pretvornika. Poseben poudarek je namenjen načrtovanju tokovnega delilnika, kjer je bila z uporabo analize dcMatch, analizirana odvisnost ujemanja tranzistorjev od njihovih dimenzij. Na tej osnovi je bila izbrana konfiguracija, ki omogoča 8-bitno ločljivost delilnika ob sprejemljivi površini. Nato sledi opis končnega vezja ter njegovega delovanja. Delovanje pretvornika je preverjeno s simulacijami in meritvami na izdelanem integriranem vezju. Doseženi rezultati potrjujejo, da pretvornik izpolnjuje vse zastavljene zahteve in je primeren za uporabo v ciljni aplikaciji.

• Language: Slovenian
• Keywords: D/A pretvornik, tokovni delilnik, diferencialni izhod, segmentirana arhitektura, CMOS
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2026
• PID: 20.500.12556/RUL-181837
• COBISS.SI-ID: 279423235
• Publication date in RUL: 16.04.2026

Secondary language

• Language: English
• Title: 12-bit current mode D/A converter with differential output

Abstract

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.

• Keywords: D/A converter, current divider, differential output, segmented architecture, CMOS