Expected growth in the three established US WLAN standards has encouraged semiconductor firms to develop low-cost amplifiers, controllers, and transceivers.
Wireless local-area networks (WLANs) have grown into one of the largest business segments in wireless electronics. According to the 225-page report, "WLAN: Wireless Data's Silver Bullet," from Forward Concepts (Tempe, AZ), more than 160 million WLAN chips will be sold by the end of 2005, with the market for WLAN network interface cards approaching $9 billion by the end of this year. These numbers indicate healthy opportunities for suppliers of WLAN integrated circuits (ICs) for many years to come.
Of course, the term "WLAN chip sets" has come to mean a variety of functions, including gain blocks, single-standard receivers and transmitters, multistandard transceivers, and medium-access controller (MAC) chips. The number of suppliers comprises a large and growing list (see table), with many of these companies offering products across the several current WLAN standards. In the US, these standards are driven by the IEEE, with the initial IEEE 802.11 standard approved in 1997 for data rates of 1 and 2 Mb/s and extended to 802.11b (now known as Wi-Fi) in 1999 for data rates of 5.5 and 11 Mb/s using direct-sequence spread spectrum (DSSS). The 802.11a standard at 5- GHz and the 802.11g standard at 2.4 GHz were established to achieve data rates as high as 54 Mb/s using orthogonal-frequency-division-multiplexing (OFDM) techniques. In Europe, the European Telecommunication Standard Institute (ETSI) has established the basic 5-GHz High Performance Local Area Network (HIPERLAN1) standard for data rates to 20 Mb/s using GMSK and the higher-speed 5-GHz HIPERLAN2 standard using OFDM for data rates to 54 Mb/s.
The most widely used WLAN standard is the original 802.11b, with many chip suppliers offering radio transceiver ICs supporting at least 802.11b and sometimes additionally 802.11g on the same device. For example, the model GRF5103 transceiver IC from GCT Semiconductor, Inc. (San Jose, CA) (www.gctsemi.com) handles both 802.11b and 802.11g at 2.4 GHz using a patented direct-conversion, zero-intermediate-frequency (zero-IF) architecture fabricated with and RF silicon CMOS process. The IC, which features a flexible interface to the baseband processor, includes a frequency synthesizer with low-noise RF oscillator and loop filter. A complete 802.11b/g transceiver can be implemented with the addition of only a single external power amplifier (PA). The firm also offers the single-standard 802.11b GRF5101 transceiver with receiver sensitivity to −88 dBm at 11 Mb/s, the GDM5302 wireless multimedia processor, and the GDM5103 controller IC, which integrates a 32-b processor, several serial interfaces, and 802.11b connectivity.
Philips Semiconductor (Sunnyvale, CA, www.philips.com) offers a dual-mode 802.11a/b/g chip set that combines the model SA5250 single-chip multi-protocol baseband/MAC IC with the single-chip model SA5251 RF transceiver. The chip set supports the 2.4- and 5-GHz WLAN bands in the US and the 4.8-GHz WLAN band in Japan for true worldwide use.
For designers seeking simplicity, Atheros Communications (Sunnyvale, CA, www.atheros.com) provides the AR5006XS single-chip solution for 802.11a/b/g. The digital CMOS chip combines a multiprotocol MAC/baseband processor with a 2.4/5-GHz radio. Operating in its Super AG™ mode, it achieves data rates to 108 Mb/s through adaptive channel-equalization techniques. It features hardware encryption for Wi-Fi protected access and extended frequency tuning range for true worldwide WLAN use.
Broadcom Corp. (Irvine, CA) recently announced two new WLAN chip sets with the company's BroadRange™ technology for increased range using 802.11g. The Wi-Fi chip set includes the model BCM4318E radio IC, which combines a 2.4-GHz radio, 802.11a/g baseband processor, MAC, and other radio components on a single device, and the BCM5352E router system on a chip (SoC) which integrates 54-Mb/s WLAN routing, Fast Ethernet switching, and a MIPS instruction-set processor on a single IC. Both ICs support the company's OneDriver™ software for enhanced performance and security. The BroadRange technology can also support SecureEZSetup™ software, a unique wizard that allows even first-time Wi-Fi users to set up a secure wireless network in just a few mouse clicks.
SiGe Semiconductor (Ottawa, Ontario, Canada, www.sige.com) supplies the model SE2521A front-end module for Broadcom's 54-Gb/s Wi-Fi systems, based on SiGe's SE2526A 802.11b/g front-end module. The firm also supplies amplifiers for WLAN systems, including the SE2528L with as much as +23 dBm output power with 3-percent error vector magnitude (EVM) in 802.11g mode. The amplifier, which can also be used for 802.11b systems, is characterized for both +3.3- and +5-VDC operation.
In the same city, IceFyre Semiconductor Corp. (www.icefyre.com) is also a fabless semiconductor company with single-standard solution for 802.11a and multistandard solution for 802.11a/b/g. The company's SureFyre™ 802.11a solution consists of the ICE5125 MAC IC, the ICE5351 combination baseband controller and RF IC, and the ICE5352 OFDM amplifier. The peak system power consumption is as low as 720 mW. The system uses per packet antenna diversity and advanced equalization techniques for as much as 10-dB improvement in sensitivity in multipath environments. The receiver sensitivity is as much as 10 dB better than the 802.11a specification while the transmitter provides as much as +23 dBm average root-mean-square (RMS) output power. The ICE5352 is a unique Class F design with 35-percent efficiency and output levels to 200 mW at 5 GHz. The company also offers the TwinFyre™ solution for 802.11a/b/g use. It basically swaps the ICE5851 dual-band MAC/RF IC for the ICE5351 single-band IC of the SureFyre chip set, coupled with the ICE5352 amplifier and the ICE5125 MAC IC.
RF Micro Devices (Greensboro, NC, www.rfmd.com) offers a complete chip set for 2.4-GHz 802.11b with its RF2958 transceiver IC, its RFS189 power amplifier, and its RF3002 baseband processor. The transceiver employs a superheterodyne architecture with on-board VCOs and synthesizer. The baseband processor incorporates antenna diversity and automatic-gain-control (AGC) algorithms along with a calibration function to reduce WLAN system manufacturing costs.
One of the best-known names in WLAN MAC and processor ICs and software is Texas Instruments (Dallas, TX, www.ti.com), which offers support for all three 802.11 WLAN variations. For example, the company's TNETW1130 is a single-chip MAC and baseband process that supports data rates to 54 Mb/s (with 802.11a and g). The device has been adopted by the Wi-Fi Alliance as part of a reference design used for 802.11g interoperability testing, and to ensure interoperability in 802.11b and 802.11g mixed-mode networks. The controller can automatically select between 2.4- and 5-GHz bands based on user-profile configurations, and optionally can be used in 802.11g+ mode for high-throughput applications.
One of the lesser-known names in WLAN radio and RF ICs is Araftek, Inc. (Fremont, CA, www.araftek.com). Short for "Advanced Radio Frequency Technology," the company supplies power and low-noise amplifiers (LNAs) for both 2.4- and 5-GHz WLANs as well as the models AR7202 and AR7501 front-end ICs for 2.4-GHz 802.11b and 5-GHz 802.11a systems, respectively.
A number of suppliers offer general-purpose amplifiers that can be used as gain blocks in WLAN systems, including Aeroflex Metelics (Sunnyvale, CA, www.aeroflex-metelics.com), Fairchild Semiconductor (South Portland, ME, www.fairchildsemi.com), TriQuint Semiconductor (Hillsboro, OR, www.triquint.com), and WJ Communications (Milpitas, CA, www.wjcommunications.com). In addition, ANADIGICS (Warren, NJ, www.anadigics.com) and Skyworks Solutions (Woburn, MA, www.skyworksinc.com) offer single-band WLAN PAs. The former, for example, offers the model RFS-P2010 for 802.11b/g use and features 22 dB gain and +23 dBm output power while draing200 mW current from a +3.3-VDC supply. The latter's SKY-65131 yields 26-dB gain from 2.3 to 2.7 GHz for 802.11b/g with better than +26 dBm output power for either standard. Skyworks recently added the model SKY65205 802.11b/g front-end module to its WLAN product portfolio. The module integrates a PA, bandpass filter, and transmit-receive switch with single-connection power supply.