| In this research, we developed a high-performance current-steering digital-to-analog (D/A) converter using 0.35 μm SiGe BiCMOS technology for communication systems such as direct digital frequency synthesizers and communication transmitters. D/A converters have become a dominant component for overall system performance. Despite the past efforts by other researches at developing D/A converters with GaAs and CMOS technologies, sampling frequency, resolution, power consumption, chip area, and production cost limit the applications of traditional D/A converters to certain systems. Therefore, the most promising candidate for GHz-range high-performance D/A converters is SiGe BiCMOS technology because of its relatively fast transient hetero-junction bipolar transistors (HBTs) as well as its sub-micron CMOS transistors.; To achieve high-performance requirements, we first addressed D/A converter design issues and methodology. Because differing architectures result in variations in static and dynamic performance, power consumption, and chip area, one must choose the appropriate D/A converter architecture with care. We evaluated several candidate architectures by behavioral modeling and simulation.; This research also proposed two types of BiCMOS current switches—a low-glitch current switch and a high-speed low-voltage current switch—for high-performance D/A converters. A current switch is the most critical component in achieving high-performance in current steering D/A converters. In this prototype D/A converter, we employ the high-speed low-voltage BiCMOS current switch, which has several advantages over the other switches.; In this work, we also propose an efficient calibration approach, suitable for a GHz-range operation. One of the most important considerations in current-steering D/A converter design is the current mismatch issue in the current-cell array. In this case, one should compensate the current mismatch issue. The proposed calibration approach significantly enhances static and dynamic linearities. |
