Mixed-Signal Circuit Design Group

The scaling of semiconductor integrated circuit technology over the past thirty years has dramatically altered the way in which information is created, stored, and communicated. Fundamental to this transformation has been a shift in the representation of information from an analog to a digital format. This shift in turn has been crucial to providing the flexibility, noise immunity, and programmability that are essential to the design of modern computing and communications systems.

In systems wherein information is represented and processed digitally, the level of overall system performance that can be attained is often limited by the interfaces between the analog and digital representations of that information. Since digitally encoded signals can be processed with virtually arbitrary precision, continued progress in the scaling of integrated circuit technology is accompanied by a corresponding pressure to improve the precision and speed of so-called data conversion interfaces. This pressure is accompanied by two related, and constraining factors: an increasing interest in embedding data conversion interfaces within large digital signal processing circuits, and explosive growth in the demand for portable electronic systems. The integration of data conversion circuits in VLSI technologies imposes severe constraints on the dynamic range available to implement those circuits, while the concern for battery life in portable systems often dictates substantial reductions in power dissipation in comparison with traditional applications.

The research projects in the Mixed-Signal Circuits group focus on a variety of issues related to the transistor-level design of both analog and digital circuits, especially with respect to the interfaces between different representations of information. In addition to the study of architectures and circuit design techniques to meet the requirements for power-efficient analog-to-digital and digital-to-analog conversion across a broad spectrum of applications, other topics of recent interest include substrate noise coupling in mixed-signal circuits, efficient power-amplification for wireless communications, and transceiver circuits for both wireless and wireline data communications.