ZigBee^® chips or 802.15.4™ chips are cost-effective, standards-based, wireless networking chips that provide low data-rates, low-power consumption, security, and reliability. ZigBee is a registered trademark of the ZigBee Alliance, a trade association that promotes this open standard. 802.15.4 is a trademark of the Institute of Electrical and Electronics Engineers (IEEE), and a reference to the IEEE 802.15.4 standard. Now maintained by the 802.15 working group, IEEE 802.15.4 specifies the media access control (MAC) and physical layers for operating ZigBee chips in areas such as 128-bit advanced encryption standard (AES) and the handling of packet-based radio protocols. The IEEE 802.15.4 standard also establishes protocols for digital radios in wireless personal area networks (WPAN).

The relationship between IEEE 802.15.4 and the ZigBee Alliance is similar to the relationship between IEEE 802.11 and the Wi-Fi Alliance. Companies join the ZigBee Alliance in order to develop 802.15.4 chips and improve the performance standards of wireless products. Manufacturers of sensor-based products which use ZigBee chips are some of the organization’s strongest supporters because these devices provide several advantages over other wireless chips and wireless products. Typically, these other technologies use a higher bandwidth and provide only limited inoperability. By contrast, ZigBee chips are relatively low-cost and offer longer battery lives. In addition, ZigBee technology uses about one-third of the stack size permitted by other IEEE 802.15.4 products. ZigBee chips are also better-suited to work with specialized, battery-operated products such as remote controls and sensors.

Types

There are several types of ZigBee chips. Receivers are designed to receive signals or data from antennas or from other devices in the system. Repeaters are interfaces that re-transmit a weak signal after increasing its power. Transmitters are designed to generate and send signals or data. Transceivers are dual devices that can operate as a transmitter and as a receiver. ZigBee coordinators (ZC) are interfaces used as main controllers. ZigBee routers (ZR) are interfaces used to transmit data from node to node in a network. ZigBee end devices (ZED) are interfaces which talk only to a parent node. They do not transmit data to any other devices in the ZigBee network. Other types of ZigBee chips are also available.

Selection

Selecting ZigBee chips requires an analysis of performance specifications and features. In terms of specifications, IEEE 802.15.4 products permit maximum data rates of 20 kilobytes per second (Kbps) at 868 megahertz (MHz), 40 Kbps at 915MHz, and 250 Kbps at greater than 2 gigahertz (GHz). In terms of features, ZigBee (802.15.4) chips use carrier sense multiple access with collision avoidance (CSMA/SA), a technology that permits a specific amount of network silence before sending a transmission. Interface, supply voltage, data rate, operating current, power dissipated, sensitivity, temperature junction, and integrated circuit (IC) package types are also parameters for ZigBee chips.