Large-scale-integrated High-efficiency Radio-frequency Devices and Their Applications to Mobile Terminals

INTRODUCTION RAPID advancement of semiconductor integratedcircuit technology has reduced the cost of mobile telecommunication terminals year by year. The global systems for mobile communications (GSM),1) which was standardized mainly by European countries, has enhanced the large scale integration of radio-frequency circuits because mobile telecommunication systems of European countries do not require very strict linearity for the radio-frequency circuits, as do systems of other countries. Fig. 1 shows the number of transistors on GSM transceiver ICs. The mid 1990s saw the development of single-band frequency (900MHz) circuit technology for GSM. Soon after, in the late 1990s, many dual-band frequency transceivers that can handle both the GSM and digital cellular system 1800 (the DCS1800) frequencies were developed. Recently, a phase-locked loop (PLL) and a low noise amplifier (LNA) were integrated in a single chip, and a radio-frequency IC was reported. This IC integrates almost all of the active radio-frequency devices of a transceiver. Furthermore, we forecast that an analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) to interface the base-band signal processing IC will be integrated on the same chip in the next few years. It has recently become popular to access the Internet using a mobile terminal. To access the Internet and transmit large amount of data, mobile terminals must have a high transmission. A new mobile system that has such a transmission rate, the IMT-2000 (International Mobile Telecommunication 2000) is under development and is now being standardized. OVERVIEW: As the design rule for integrated circuits becomes smaller and smaller, the number of transistors that can be integrated on a single chip becomes larger and the output and dissipated power efficiency of radiofrequency circuits becomes higher. These qualities make mobile telecommunication terminals using radio-frequency integrated circuits less expensive. In the near future the number of transistors integrated in radiofrequency integrated circuits is forecasted to be over several tens of thousands. These circuits with improved linearity have been a major contributor to data telecommunication such as mobile access to the Internet. Hitachi, Ltd. developed three new radio-frequency integrated circuits: (1) a bipolar complementary metal-oxide semiconductor (Bi-CMOS) analog signal processing IC, (2) a GaAs low noise amplifier (LNA) and mixer (MIX) monolithic microwave IC (MMIC), and (3) a dual-band radio-frequency power amplifier module. They are designed to achieve large-scale integration and high efficiency. In the future, we plan to develop low-distortion, largescale-integrated, high-efficiency devices for the third generation of mobile telecommunication systems.