Edward T. Spears

High-Efficiency Cellular Power Amplifiers Based on a Modified LDMOS Process on Bulk Silicon and Silicon-On-Insulator Substrates With Integrated Power Management Circuitry

An RF high-voltage CMOS technology is presented for cost-effective monolithic integration of cellular RF transmit functions. The technology integrates a modified LDMOS RF power transistor capable of nearly comparable linear and saturated RF power characteristics to GaAs solutions at cellular frequency bands. Measured results for multistage cellular power amplifier (PA) designs processed on bulk-Si and silicon-on-insulator on high-resistivity Si substrates (1 kΩ·cm ) are presented. The low-band multistage PA achieves greater than 60% power-added efficiency (PAE) with more than 35.5-dBm output power. The high-band PA achieves 45%-53% PAE across the band with greater than 33.4-dBm output power. Measured linearity performance is presented using an EDGE modulation source. A dc/dc buck converter was also integrated in the PA die as the power management circuitry. Measured results for the output power, PAE, and spurious emissions in the receive band while the dc/dc converter is biasing the PA and running at different modes are reported.

Average current reduction in (W)CDMA power amplifiers

Statistical average current consumption of conventional CDMA and WCDMA [(W)CDMA] power amplifiers is compared to that obtained by using DC-DC converters, analog bias control, and low power efficiency enhancement (LPEE) techniques. A discussion of theoretical limits, strengths, and weaknesses for each approach is presented

Design of High-Order Switches for Multimode Applications on a Silicon-on-Insulator Technology

A silicon-on-insulator (SOI) CMOS technology on high-resistivity silicon substrates is presented for the design of high-power switches for cellular and wireless local area network handset applications. A design methodology is introduced to design high-order switches for optimal insertion loss and isolation performance. Sources of nonlinearities in SOI switches are discussed. To the best of our knowledge, this work is the first demonstration of high-power switches on a high-resistivity SOI CMOS technology for high-volume cellular handset applications with adequate intermodulation and harmonic distortion performance. The design details and measurement results for a variety of RF switches with general-purpose input/output and mobile industry processor interface control interfaces, flip-chip/wire-bond packaging, and for various standards are discussed.

RFCMOS SOI technology for 4G reconfigurable RF solutions

In order to provide increasing data rates demanded by the consumer market, the 4G RF cellular front-end is becoming increasingly complex with numerous transmit and receive bands, the possibility of multiple antennae and new architectures which involves Uplink and Downlink carrier aggregation. Such new architectures present extreme challenges for conventional fixed band systems composed of PAs, switches and filters. Tunable technologies using RFCMOS SOI technology are already being deployed in increasing number in todays advanced RF cellular handsets. The talk will present a chronology of the RFSOI technology development in the industry through the last decade and highlight novel uses of its capabilities in 4G systems as well as the critical specifications needed in this application space.

DC/DC converter controlled power amplifier module for WCDMA applications

A single package power amplifier module with a GaAs PA and a Si DC/DC converter for WCDMA application is presented. Integration of a linear power amplifier and a power management chip is implemented to improve the efficiency of the PA at low output power by changing the supply voltage. Overall PA performance at 27.5dBm is identical to the discrete WCDMA power amplifier and the efficiency at 16dBm output power is improved from 8 ~ 9% at 3.4V supply voltage to 16.8% with the DC/DC converter. Receive band noise power is minimized to -135dBm/Hz at 190MHz offset by noise reduction techniques in the module

Advances in SOI switched capacitors for 4G tunable antennas

In order to provide increasing data rates demanded by the consumer market, the 4G RF cellular front-end is becoming increasingly complex with numerous transmit and receive bands, the possibility of multiple antennas and new architectures which involves Uplink and Downlink carrier aggregation. Such new architectures present extreme challenges for conventional fixed band systems composed of PAs, switches and filters. Tunable technologies using RFCMOS SOI technology on high resistivity substrates are already being deployed in increasing numbers in todays advanced RF cellular handsets. This paper will present a discussion on RF topologies and architectures enabled by modern RFSOI technologies to solve the increasingly complex 4G RF front-end, including a discussion of the critical specifications needed in this application space.