Many of today's engineers and designers hope to make the switch from wired electronics to their wireless counterparts. Factoring in installation, this migration typically provides a great deal of cost savings. But the adoption of wireless technology isn't always as easy as it sounds. The primary obstacle is that radio-frequency (RF) technology is a specialized field of expertise. It's not easily shared by all engineers and designers. How can a non-RF expert reap the benefits of wireless technology while at the same time mitigating risk? If the desired wireless solution will play in the 860-to-926-MHz frequency range, designers can now seek help from Honeywell International's HRF-ROC093XC radio-on-a-chip transceiver (FIG. 1).

Even if they have little or no experience in radio technology, this transceiver claims to help designers make the switch to wireless. It's well suited to digital voice and data applications in the home, office, or industrial setting. In those scenarios, monitoring is conducted from either a mobile or stationary point. The HRF-ROC093XC also can be utilized in applications as diverse as surveillance systems, medical-sensor communication, multi-node networks, and electronic gaming and toys.

For an embedded-microcontroller designer who wants to add wireless communications to an existing product, this transceiver promises a relatively simple and low-cost answer. Of course, it also is a viable solution for the radio-based products that are in need of a performance boost or cost reduction. Such devices might include thermostats, real-time industrial monitoring, modems, and two-way transceivers.

For its widespread applicability, the Honeywell HRF-ROC093XC radio-on-a-chip transceiver can thank an obvious source. As a fully integrated device, it features a smaller component count. It's therefore lower in cost than other older, discrete-based radios.

With the HRF-ROC093CX transceiver, for example, microcontroller functions that address and store the data have already been incorporated on chip. This approach lowers overall radio cost. It also reduces the workload of an external microcontroller, which is needed to communicate with the transceiver. As a result, operating the transceiver requires little more than a low-cost off-the-shelf microcontroller, an antenna, and a 2.5-V power supply. Cost savings also is derived from a streamlined design process, which is enabled by the Honeywell transceiver.

The HRF-ROC093XC is a 2.5-V, all-CMOS, programmable wireless transceiver. It's fabricated on a 0.25-µm process. On chip, it integrates an RF signal synthesizer, Frequency Shift Keying (FSK) transmitter, direct-downconversion receiver, and a digital interface (FIG. 2). It operates at data rates up to 128 kbps under license-free Federal Communications Commission (FCC) Part 15.247 and 15.249. The transceiver flaunts a range of 2000 ft.

Communication takes place on a single channel or on multiple channels for short-range applications. In applications where a longer range is desired, the transceiver can operate as a frequency-hopping spread-spectrum (FHSS) radio. In this scenario, the ability to use a higher transmit power and multiple channels vows to significantly reduce interference from other radios. To change frequencies or channels, the user only needs to write to one internal register. Honeywell even developed frequency-hopping software for its transceiver. It maintains communication synchronization and reliable message transfer.

Specific characteristics of the HRF-ROC093XC transceiver include an Rx sensitivity of −95 to −100 dBm with 6 dBm maximum of transmitter power. In transmit mode, the transceiver has a DC current of 30 mA. In receive mode, that current is 37 mA. The HRF-ROC093XC boasts 64-B FIFO on-chip data storage, a 32-b programmable message address, and an on-chip radio-frequency switch.