The moves by the two electronics giants put them both in a position to serve the auto industry, which plans to incorporate chips in as many as 50 million tires per year by 2005.

The two companies, along with more than a dozen other electronics suppliers, are scrambling to put the capabilities in place to meet a federal mandate from the National Highway Traffic Safety Administration that calls for vehicles to incorporate tire-pressure-monitoring systems starting later this year. According to the mandate, 10 percent of the 16 million vehicles sold annually in the United States must have the monitoring systems by November 2003. The requirements jump to 35 percent in 2004 and 65 percent in 2005.

In the best cases, the federal government estimates, such smart-tire technologies could prevent more than 10,000 injuries and 70 deaths per year.

"The market for tire pressure monitoring is going to be big," said John McGowan, senior marketing manag-

er for Infineon North America's Automotive and Industrial Group (Northville, Mich.). "What remains to be seen is what kind of monitoring system the automakers will want to use," he said.

Growing market

By agreeing to acquire SensoNor ASA (Horten, Norway), Infineon showed that it plans to pursue a technique known as "direct" tire pressure monitoring, which is expected to emerge as the most popular method over the next decade. In direct tire pressure monitoring, suppliers place pressure sensors and radio frequency (RF) transmitter chips inside the tires, either on the stem, on the rim, or within the tread. The pressure sensors and transmitter chips then send RF signals to a receiver, or "head unit," in the dashboard. The receiver works with dash-mounted displays to communicate tire pressures and warns the driver if a tire is underinflated. The direct technique is expected to overtake the "indirect" method, which uses antilock brake wheel speed sensors to measure the rotational speed of each tire, and therefore infer whether one tire is low. More than 2 million General Motors and Ford vehicles currently use the indirect technique.

In the U.S. alone, electronics suppliers say they foresee a potential annual market for about 10 million new vehicles, each with five tires (including the spare), to employ tire-mounted pressure sensors by 2005. The percentage of U.S. vehicles using the technology is expected to continue to climb after 2005 as well. In addition, European and Asian automakers plan to incorporate the technology.

Infineon said last week that its acquisition of SensoNor will help it become the market leader in the tire pressure sensor segment. Infineon executives said they expect to pay about 48 million euros (about $56,196,000) to complete the acquisition, and added that they expect it to double their market share of automotive sensors to about 15 percent.

SensoNor makes application-specific integrated sensors based on piezoresistive pressure that are used by tier-one suppliers in their tire-pressure-monitoring systems. Users of the technology include TRW Automotive (Livonia, Mich.) and SmarTire Systems Inc. (Richmond, British Columbia), among others.

SmarTire will incorporate SensoNor sensors in its tires.

SmarTire last week announced that it has signed a memorandum of agreement for SensoNor to supply sensors for SmarTire's RF transmitters, which have been incorporated by Siemens VDO (Auburn Hills, Mich.) and Goodyear USA (Akron, Ohio).

Low-power designs

Similarly, Motorola last week prepared for the new demand for smart tires by rolling out an automotive tire pressure sensor that it said consumes about one-tenth as much power as competing units.

By introducing the low-power design, Motorola hopes to lengthen the time that a sensor can perform in a tire without needing to be replaced or requiring installation of a new battery in the tire.

The electronics giant said that the new sensor, housed in a supersmall-outline package measuring 0.3 inch on a side, is one piece of an electronics puzzle that could enable TPM systems makers to achieve a 10-year battery life in their products.

"It's directly targeted at the tire-pressure-monitoring market," said Mark Shaw, manager of systems engineering for Motorola's sensor products (Tempe, Ariz.). "If we had built this for any other market, we wouldn't have paid as much attention to power consumption."

The new pressure sensor departs from the conventional in that it is a surface micromachined capacitive type, whereas most TPM sensors use bulk micromachined piezoresistive technology. Motorola engineers said that because it employs capacitive technology, it can be made smaller and less power-hungry. A low-power standby oscillator in the device keeps time and wakes up a measurement system's microcontroller system as needed, thus sharply reducing the device's standby current requirements.