Electronic Design

Short-Range WirelessUSB Could Give ZigBee Fits

How many short-range wireless solutions are there? There's 802.11, Bluetooth, ZigBee, Utlra Wideband (UWB), and a hodgepodge of other products using the 27-, 433-, 868-, 915-, and 2400-MHz unlicensed bands. Now, there's WirelessUSB from Cypress Semiconductor, too.

Actually, WirelessUSB isn't that new. It was first introduced last year for use in short-range (<10 meters) applications, particularly PC peripherals and toys and games. Yet Cypress' WirelessUSB LR chip has a range up to 50 meters, opening the door to a host of applications.

The basic WirelessUSB product operates in the 2.4-GHz ISM band. It uses direct-sequence spread spectrum and has a 62.5-kbit/s data rate. The newer version also supports point-to-point and point-to-multipoint networking with up to 65,536 nodes. The circuitry, RF, and the digital interface are all on one chip. Such specs are like the low-end ZigBee radios on the horizon. But WirelessUSB is here now with more simplicity for applications that don't need complex networking links and negotiations. The result is a radio that's just below ZigBee in cost and complexity.

The WirelessUSB LR fits the industrial monitoring and control market. It's well suited for remote wireless sensors in chemical plants, factories, and similar environments. Building automation is another target, where it can simplify temperature and light monitoring as well as A/C and heating control. The radios should also find use in transportation, remote meter reading, retail automation, home automation and security, alarms, barcode scanners, and remote controls of all types.

ZigBee is similar, with some key differences. First, the WirelessUSB radios are smaller and less expensive. Next, they're far less complex to design with: Other than a power source and antenna, there are few external components. And without the complexity of implementing mesh and other forms of ad hoc networking, product and system design is much simpler.

As for specifications, the WirelessUSB LR features a 0-dBm (1 mW) transmitter, a receiver with a −95-dBm sensitivity, and a data rate of 62.5 kbits/s with a latency time of less than 10 ms. Standby current is only 0.25 µA, and battery life is literally years. Finally, the operating temperature range of −40°C to 80°C makes it a good fit in many hostile industrial environments.

The WirelessUSB LR comes in a 48-pin QFN package for commercial applications. It costs $2.93 in 50,000-unit lots. An industrial-temperature version in the same package runs $3.93 in the same quantity. The device also comes in a 28-pin SOIC package for $3.70 in 50,000-unit lots. Samples are available now. Full production quantities are slated for midyear.

Cypress Semiconductor Inc.

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