Marcus Granger-Jones

A broadband high-dynamic-range voltage-controlled attenuator MMIC with an IIP3 > +47 dBm over entire 30-dB analog control range

In this paper we introduce a novel design technique for broadband high dynamic range absorptive voltage controlled attenuators (VCA) on SOI CMOS. The VCA design is based on the classical passive FET ‘Pi’ and ‘Tee’ attenuator structures but uses stacked FET techniques to dramatically improve the signal handling capability. The VCA has >30dB attenuation range over a frequency band from DC to > 5GHz and achieves an IIP3 of > +47dBm over the entire analog control range. The use of a stacked FET structure evenly distributes the RF signal across ‘N’ FET devices thus reducing the 3rd order distortion generated by each individual FET. The reduction in distortion gained is directly proportional to the degree of stacking used.

A 50MHz–16GHz low distortion SOI voltage controlled attenuator IC with IIP3 > +38dBm and control range of > 25dB

This paper discusses a 50MHz–16GHz wideband, low distortion, voltage controlled attenuator (VCA) on silicon on insulator (SOI) CMOS technology. The VCA design is based on passive FET absorptive attenuator structures but uses stacked FET techniques to dramatically improve the distortion characteristics and signal handling capability. It leverages a surface mount compatible flip chip IC in an over molded laminate package to minimize parasitics. The VCA achieves >25dB attenuation range, IIP3 of > +38dBm and IP1dB > 25dBm up to 16GHz. The laminate and flip chip combination maintains a return loss of better than −8dB over the entire frequency and attenuation range. The insertion loss at 16GHz is 5.0dB at minimum attenuation.

Carrier aggregation and its challenges - or: The golden age for acoustic filters

With the advent of LTE-Carrier Aggregation (CA) as a means of increasing data rates in mobile device communication, a paradigm shift in the design of acoustic filters has been arising. Whereas before CA the focus of filtering has been on supporting one telecommunication band at a time, now multiple bands will have to be supported simultaneously over the same antenna. As a consequence, using switched filter banks is not an option anymore, and the only viable solution is to connect multiple Tx, Rx, and/or TDD filters to the same antenna pin. In this multiplexing configuration, several additional challenges need to be addressed when designing the individual filter components. The traditional requirements (low insertion loss, good out-of-band attenuation, tight impedance locus, good IMD behavior, power handling, and - in case of FDD bands - the highest possible Tx-Rx isolation) are no longer sufficient. Now designers also need to minimize loading of multiple filters by all the other filters out-of-band impedance, optimize a multitude of cross-isolation requirements, and worry about a plethora of nonlinear mixing products (IMDx). This presentation provides an overview of these new challenges and discusses strategies to address some of them. Case studies will be reviewed and the next challenges lurking behind the horizon will be revealed.