A 12-bit, 500 MHz, current steering DAC for use in an FMCW radar system

Date

2020-08-01

Journal Title

Journal ISSN

Volume Title

Publisher

Kansas State University

Abstract

Digital-to-analog converters are an essential part of modern electronic systems which demand low-power consumption, high-speed performance, and exceptional linearity. They have a seemingly infinite number of applications, and as commercial integrated circuit processes continue to delve further into deep sub-micron territory, their utility, performance, and efficiency will only improve.

This thesis focuses on the design and implementation of a 12-bit, 500 MHz, current steering DAC in a 45nm SOI CMOS process. The DAC was designed using a fully-segmented, or ‘thermometer-coded’ topology, and will be fabricated in the aforesaid process. Ultimately, the DAC is destined for integration in a K-band stepped-frequency FMCW radar system, where it will act as an intermediary between a direct-digital-synthesis submodule and a phase locked loop submodule. – The DAC will convert the DDS produced discrete-time sinewave output, which has a low over-sampling ratio, to an analog continuous time waveform suitable for bandpass filtering. Bandpass filtering then provides time-smoothing to improve phase noise and spurious levels from the PLL.

To fully realize a workable DAC, several other sub-systems exist which contribute to its overall function. The design and implementation of these sub-systems – digital thermometer decoders, D-Flip-Flops, and individual current cells – will be described in detail. Trade-offs and challenges encountered throughout the ‘creation-story’ of this system are also discussed.

Description

Keywords

DAC, Radar, FMCW

Graduation Month

August

Degree

Master of Science

Department

Department of Electrical and Computer Engineering

Major Professor

Don M. Gruenbacher

Date

Type

Thesis

Citation