Integrated temperature Sensor in passive RFID

With a typical measurement accuracy of up to 0.5°C, the EM4325V11 is ideal for wireless real-time or data-logged monitoring of perishables.

EM Microelectronic has announced the EM4325V11, a versatile and multipurpose, battery-assisted passive (BAP) RFID chip with a calibrated temperature sensor. This chip enables accurate remote temperature monitoring using industry standard EPC™ Gen2 wireless protocol. Temperature data logging can easily be implemented with a companion microcontroller connected to the EM4325V11 via a standard SPI interface.

The integrated temperature sensor monitors ambient temperature from -40°C to +60°C with 9-bit measurement accuracy of up to 0.5% over the full temperature range. In pure passive mode, the temperature sensor can be used for field-powered snapshot readings. But the chip can also be programmed to perform self-monitoring with user-programmable alarm conditions (upper and lower temperature thresholds). Self-monitoring operation is supported with an on-board real-time clock (RTC) to control sampling intervals and provide a timestamp for alarm conditions. The sensor may be configured to provide Simple Sensor Data reporting according to the data formats defined in ISO/IEC 18000-6 and ISO/IEC 24753.

Operating in the UHF frequency range, the EM4325V11 is compliant with the following standards:
• ISO/IEC 18000-6 Type C and Type D (TOTAL)
• EPC™ Class 1 Gen2
• AIAG™ B-11
• ATA 2000

The EM4325V11 expands the viability of UHF RFID for new applications by offering longer read range, increased communication robustness and more configuration options and interface capabilities for auxiliary functions. EM Microelectronic designed all the EM4325 ICs with an advanced feature set which leads to performance and functionality well beyond that of ordinary Gen2 chips.

EM4325’s BAP RFID technology combines the lower complexity, simpler communication protocols and lower cost of passive RFID with significantly higher read range and increased communication robustness available with active RFID. The EM4325V11 operates in both BAP and purely passive modes. It integrates smart power management for longer battery life when used in BAP applications. The EM4325V11 also allows programmable duty cycle and automatic switching between battery-powered and field-powered operation when the tag is too far away from the reader. A unique ultra-low power (ULP) mode can be activated or disabled via a simple reader command. The ULP mode extends tag battery life when the tags are stored for long periods.

The EM4325V11 further contains 4 kbits of high speed, non-volatile memory (EEPROM). It supports either ISO or EPC™ data structures compliant with EPCglobal®’s Tag Data Standard, Version 1.6. To ensure full traceability, the chip is delivered with a factory programmed and serialized Unique Identifier (UID).

The EM4325V11 has a programmable external interface for auxiliary functions and a 4 bit I/O port. These interfaces open the door to advanced applications where it can be operated either as an RFID tag or as an RFID interface or modem for embedded applications. The auxiliary function may be configured as input for tamper detection or as an output to notify external devices of RF events. The 4 bit I/O port can be programmed to support 4 discrete signals or as a Serial Peripheral Interface (SPI) configurable as an SPI master or slave device.

Thanks to its rich feature set, the EM4325V11 can thus be used in a variety of use cases: Standard Supply Chain Management: EPC™ Gen 2 was developed to establish a standard for RFID tags used in supply chain applications (e.g., tracking inventory). The EM4325V11 is fully compliant with this standard. It also integrates additional security features such as its factory programmed and permanently locked unique ID to prevent tag cloning and a 32bit password protected access command. It can be operated in purely passive mode or in BAP mode when longer reading distances are required. Cold Chain Temperature Monitoring: In BAP mode, the internal temperature sensor of the EM4325V11 can be configured for self-monitoring operations with defined alarm levels, thus allowing the detection of disruptions in the cold chain. Fast and easy reads can be performed at each transfer of custody to guarantee the quality and security of the received goods (e.g. food, medical products), thus increasing profitability and delivered freshness  Automatic Vehicle Identification (AVI): BAP technology avoids the pitfalls of both passive and active RFID in AVI applications; it is significantly less expensive than active RFID but offers excellent read performance at high speeds and at long range, even in wet conditions. In BAP mode, the EM4325V11 offers -31dBm read sensitivity at chip level, which corresponds to open-field read ranges in excess of 50 meters. Product configuration and control: The EM4325V11 can be implemented as an embedded RFID interface or modem in a more complex system; with 4kbit of memory, it can be used as a Gen2-compliant communication channel for configuration operations. Specific parameters (e.g. pairing information for wireless devices) could be programmed into products which are already packaged, but which are not yet powered. Once the product is unpacked and switched on, it could read these parameters via the SPI interface on the embedded tag. Furthermore, the availability of an RFID tag which is not just attached to an item, but which is truly integrated into and interfaced with a wide variety of consumer electronic devices enables many new opportunities for the “Internet of Things”. Tamper Detection: The EM4325V11 can be configured to support a seal tamper sensor that detects breakage or removal of a seal strap. It is an ideal building block for a variety of electronic seal (e-seal) applications (e.g. container security or access control of sporting or cultural events by non-transferable RFID wrist bands). RFID for Challenging RF Environments: In BAP mode, the EM4325V11 provides increased read reliability for bulk reads at longer distances or in challenging real-life environments with higher liquid or metal density and/or noisy RF communication environments.

• For more information on EM’s RFID and NFC solutions, refer to their Vendor Information on RFID Connect .