RFID IC avoids collisions, reads at greater-than-15m distances
By Nicholas Cravotta -- EDN, May 27, 2004
EM Microelectronic's new EM4223 UHF RFID IC fully complies with the international standard ISO18000-6A and EPC (Electronic Product Code) 64- and 96-bit code specifications. Air interface ISO18000-6A, which ISO finalized in 2003 and plans to publish in the coming months, also defines families of items to store in the AFI (application-family-identifier) segment of memory. Using AFI, the EM4223 supports a direct-selection mechanism, which enhances throughput by reducing the data flow through the network. For example, AFI enables a reader to read only specific types of items, even though many types may be present.
The EM4223 chip targets use in UHF passive, read-only transponder applications, such as security and access control, supply-chain management, anticounterfeiting, parcel and baggage tracking, pharmaceuticals, biologistics (such as animal ID), and toll-road collection. The 128-bit, read-only UHF circuit is frequency-agile across 800 MHz to 2.5 GHz for RF-propagating field applications. It complies with worldwide radio regulations and can read tags at distances greater than 15m when using an optimized transponder antenna (Picture). RFID ICs receive and rectify an RF beam that a reader transmits, thus powering the chips. They transmit information back to the reader using passive backscatter modulation, in which the chip varies the amount of energy that the chip’s antenna circuit reflects.
The EM4223 offers an enhanced anticollision protocol, which avoids transmission channel saturation. This technology allows a reader to potentially read more than 1000 simultaneously present tags at 200 EM4223 tags/sec. The protocol also supports mobile tags that enter or leave the field without corrupting the anticollision protocol and preventing other tags from being read. Fast reading of user data during arbitration also speeds operation.
Currently available for sampling, the EM4223 should enter production in the second quarter and sells for less than 10 cents (high volumes). More information is available at www.emmicroelectronic.com/Products.asp?IdProduct=210.
EM Microelectronic , 1-719-598-9224, www.emmicroelectronic.com.
