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Electronic Design

Single-Chip Wi-Fi Radio For Portables Takes Off

The AirForce OneChip BCM4317 transceiver IC, a complete single-chip 802.11b radio, is small enough, cheap enough, and low-power enough to be built into PDAs, cell phones, MP3 players, and digital cameras. Undoubtedly, this Broadcom device will open up automotive applications, home entertainment devices, and other previously untapped markets as well. Even low-end laptops are in the chip's periscope.

Current two-chip 802.11b solutions are too large and power-hungry for handheld devices. Also, both chips must have upwards of 200 discrete components, particularly in between the RF chip and the antenna. The baluns, receiver/transceiver and diversity switches, and other parts occupy lots of space in addition to bumping up cost.

The BCM4317 puts the RF transceiver and the baseband circuits into one 0.13-┬Ám CMOS chip. Most of those discrete components near the antenna have been integrated, too. Even the 15-dBm linear power amp is on-chip. The only external components are two low-pass filters in the input, the crystal, and any external memory required. The total number of discrete components was reduced from over 200, which is normal, to about 30. The figure shows a complete module using the new chip. This is one of three reference designs available for this new part.

The BCM4317's innovative power-management system helps extend battery life in small portable devices with inherently weaker batteries. Tests show that this feature consumes 75% to 80% less power than any other wireless local-area network (WLAN) chip set. The chip's SuperStandby mode puts the chip into a deep-sleep state that conserves power by suspending wireless activity for microseconds rather than continually looking for incoming data. In this mode, the chip consumes less than 1 mW of power, while previous WLAN chip sets consumed more than 600 mW.

The three reference designs help accelerate time-to-market. The reference design module shown in the photo is about the size of a stamp and 90% smaller than traditional CardBus designs. With the BCM94317SD and BCM94317CF production-ready modules, designers can easily add 802.11b to cell phones, PDAs, and cameras. The BCM94317SB integrates the 802.11b capability with Bluetooth on the reverse side of the module.

Finally, the BCM4317 includes all of the other features of Broadcom's line of WLAN chip sets, such as Wi-Fi Protected Access (WPA), AES encryption hardware, and Cisco's Compatible Extensions (CCX).

All of these products are currently shipping in sample quantities to Broadcom's early access partners. Volume production will be available in the first quarter of 2004, with pricing expected to be $10 each in quantities of 50,000 units.

Broadcom Corp.
(949) 450-8700

TAGS: Automotive
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