em|echo-V

The EM|echo-V is a dual-frequency RFID tag IC combining two independent RFID interfaces in a single die. The UHF interface operates at 860–960 MHz compliant with ISO/IEC 18000-63 (EPC Gen2), using passive backscatter modulation with FM0 or Miller encoding and FM0/Miller subcarrier modulation for reader-to-tag and tag-to-reader communication respectively. The HF interface operates at 13.56 MHz compliant with ISO/IEC 15693, using 1/4-subcarrier load modulation at 26.48 kbit/s or 6.62 kbit/s data rates with ASK 10% or ASK 100% modulation for reader-to-tag communication.

The chip integrates an EM4237-based HF section (ISO 15693) with a UHF RFID inlay section (EPC Gen2). Each interface has independent memory and state machines, with no memory sharing between the two RF front-ends. Anti-collision on the UHF port uses the EPC Gen2 Q-algorithm with dynamic slot counting; the HF port uses the ISO 15693 slotted ALOHA anti-collision mechanism. Both interfaces are powered exclusively via RF energy harvesting with no external power source required.

Memory Architecture

The UHF section implements standard EPC Gen2 memory banks: Bank 00 (Reserved/Kill and Access passwords), Bank 01 (EPC identifier), Bank 10 (TID/Tag ID), and Bank 11 (User memory). The HF section implements ISO 15693 block-oriented EEPROM with single-block and multiple-block read/write capability. The two memory spaces are not synchronized; data written via HF is not accessible via UHF and vice versa.

Potential applications for the EM|echo-V include:

• Supply chain logistics requiring both short-range HF interrogation for item-level processing and long-range UHF reading for pallet/case-level tracking
• Asset tracking in environments where infrastructure mixes HF and UHF reader installations
• Transition scenarios where legacy ISO 15693 HF infrastructure coexists with newer EPC Gen2 UHF deployments

The dual-frequency nature allows a single tagged item to participate in both HF-focused workflows (proximity access, NFC-style interaction) and UHF-focused workflows (bulk inventory, portal reading) without requiring two separate tags. Potential use considerations include managing independent data on each interface and accounting for differing read ranges (HF typically centimeters, UHF up to meters).

Reader compatibility requires dual-standard capability: EPC Gen2 UHF readers for the 860–960 MHz interface and ISO 15693-capable HF readers for the 13.56 MHz interface. No single command set operates both interfaces simultaneously.

UHF (EPC Gen2) Commands

Standard EPC Gen2 command families apply: Query, ACK, NAK, REQ_RN, READ, WRITE, KILL, LOCK, ACCESS, BlockWrite, BlockErase. Memory bank access follows EPC Gen2 partitioning. The TID bank contains EM factory-programmed identifier data.

HF (ISO 15693) Commands

Standard ISO 15693 command set: Inventory, Stay Quiet, Read Single Block, Write Single Block, Lock Block, Read Multiple Blocks, Write Multiple Blocks, Select, Reset to Ready, Write AFI, Lock AFI, Write DSFID, Lock DSFID, Get System Information, Get Multiple Block Security Status. The AFI (Application Family Identifier) and DSFID (Data Storage Format Identifier) are configurable per block.

Integration Pitfalls

Critical: both interfaces share the same physical die but have no data synchronization. Writing EPC data via UHF does not update HF memory contents, and conversely. Applications requiring data consistency across both frequencies must implement external database correlation using the respective unique identifiers (EPC for UHF, UID for HF). The HF UID is factory-fixed and not modifiable; the UHF EPC is typically writable but may be locked.

Near-simultaneous energization of both RF fields may cause power arbitration issues; typical deployment assumes exclusive activation of one interface at a time. The chip does not specify a command for cross-interface state query—interface selection is purely physical-layer determined by which frequency energizes the tag.

• Confirm exact part number and revision with EM Microelectronic, as the EM|echo-V designation may have multiple die revisions or wafer/delivery forms
• Request current datasheet revision date and errata documentation
• Clarify whether delivery is bare die, bumped die, or assembled inlay; the product description references "inlay" format but verify exact mechanical form factor
• Specify operating temperature grade and storage conditions, particularly if the dual-frequency architecture affects thermal derating versus single-frequency alternatives
• Validate that supplied samples operate correctly on both HF and UHF ports with your target readers; verify TID and UID contents against factory programming expectations
• Confirm HF memory block count and UHF user memory size, as EM|echo-V variants may differ in memory allocation between the two interfaces
• Request guidance on expected lifecycle status and any migration path from constituent products (EM4237-based designs or prior EM dual-frequency offerings)