The company has developed 1.5-Mbit/second BiCMOS transceivers that operate in the 5.8-GHz frequency band, and Uniden America Corp. plans to use them in its cordless telephones. Uniden said its 5.8-GHz phones are free from the interference that's starting to surface in the 2.4-GHz ISM band, which will soon be overcrowded, the company said.

The cordless-phone transceivers will point Micro Linear toward profitability in 2003, said Timothy Richardson, who became president and chief executive officer of the San Jose, Calif., supplier last May. The company is exploring other applications for transceivers in the 5.8-GHz range, as well as higher data rates for its BiCMOS and silicon germanium parts.

Seeking turnaround

Like many other suppliers, Micro Linear is in search of a turnaround. The company reported a net loss of $2.8 million on revenue of $28.7 million for the year ended Dec. 31, 2002. That revenue represented a 30 percent increase over the previous year, when losses totaled $16.2 million.

Founded roughly 20 years ago, Micro Linear once focused on customizable linear arrays and modifiable application-specific standard products. Hard-disk-drive makers were key customers for Micro Linear's array-based products. But while the arrays offered rapid time-to-market, they utilized large amounts of silicon and consequently could not compete on a cost basis with full-custom designs.

Micro Linear's decision to vacate the linear-array business left it without a clear focus.

It trailed Linear Technology Corp. and Maxim Integrated Products Inc. in terms of analog craftsmanship, and lost volume sales to National Semiconductor Corp. and Texas Instruments Inc. Attempts to compete in the Pentium processor core voltage-regulator market proved to be short-term, and the company sold its power-management business to Fairchild Semiconductor in 2000.

Shedding the power-management activity allowed the company to focus on RF components-building blocks and integrated transceivers for 900-MHz, 2.4-GHz and 5-GHz applications. But when competition in the 2.4-GHz component sector became fierce, Micro Linear attempted to carve out a leadership position in the 5-GHz ISM band, developing transceivers capable of 108-Mbit/s data transfers, Richardson said. Shifting standardization efforts frustrated some of the company's efforts; Richardson called the IEEE's adoption of the 802.11g standard an "unfortunate event."

Richardson, who became CEO amidst a drain on capital and manpower, developed a formula to capitalize on the company's forays into the 5-GHz region. A former vice president of Beacon Electronics, Richardson had been on the Micro Linear board since May 2001. The company at that time was already delivering 900-MHz and 2.4-GHz building blocks to Uniden for its cordless phones. Richardson wondered about the utility of a part that operated at a slower data rate in the 5-GHz band-say, at 1.5 Mbits/s.

Less clutter

The result is the ML5800, a 5.725-GHz to 5.85-GHz band radio used in Uniden's latest cordless-phone set. The 300-MHz swath is still relatively free of the wireless-LAN traffic, microwave-oven noise and video-camera transmissions that now clutter the 2.4-GHz ISM band, Richardson said.

The ML5800 is a direct-sequence spread-spectrum FSK device that transmits and receives 1.536-Mbit/s signals in 2.048-MHz-spaced channels. The device integrates practically all the frequency generation, receiver and transmit functions on one BiCMOS device.

SiGe is used as the bipolar implant on a CMOS substrate because it's cheaper at these frequencies than straight CMOS, Richardson said. An external low-noise amplifier, power amplifier and antenna T/R switch are required to complete the transceiver function.

The single-chip ML5800 is expected to ship in volume later this year. Uniden's current 5.8-GHz phones-priced from $149 to $229-are using a module implementation of the part.

In addition to digital cordless phones, Micro Linear believes the transceiver could support MP3 audio- or video-streaming applications in wireless PDAs or wireless computer game controllers.

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