Alessandro Piovaccari

A harmonic rejection mixer robust to RF device mismatches

Harmonic rejection (HR) mixers are key building blocks in wideband receivers such as TV tuners and software-defined radio receivers employing low-IF or direct downconversion. In TV tuners, in-band HR in excess of 72dB is desired. A mixer capable of high harmonic-rejection ratio (HRR) is needed to relax the requirements on pre-mixer RF filters, which are expensive and bulky. HRR for conventional HR mixers [1] is limited by mismatches amongst devices operating at RF frequencies (shown in Fig. 3.8.1). Reducing mismatches by increasing device area to achieve high HRR comes at a severe cost of power, area and RF bandwidth. This matching requirement at RF frequencies limits the achievable HRR to be only between 30 and 40dB [2,3]. Recently, two-stage HR mixers have been proposed [4]. While [4] has reduced gain errors, phase errors that limit the achievable HRR are still determined by device matching at RF frequencies.

Session 2 — Low power analog

This session presents existing design challenges in ultra-low power circuits and proposes architecture and circuit techniques to overcome those challenges. The first paper (invited) discusses the fundamental limits analog circuits face specifically due to scaled technologies and discusses some design strategies and innovative approaches to alleviate them.

Over-sampled data converters

The papers in this session highlight both emerging applications of over-sampling techniques and newer methods of their implementation in traditional analog-to-digital converters architectures. Performance enhancement techniques for both discrete- and continuous-time oversampled analog-to-digital converters are presented. Application of over-sampling and noise-shaping techniques to the design of high performance speaker drivers is also demonstrated.