EM4543

The EM4543 operates at 125 kHz and implements the ISO 11784/11785 protocol suite, supporting both FDX-B (Full Duplex) and HDX (Half Duplex) communication modes. In FDX-B mode, the chip continuously transmits its identification code using amplitude-shift keying (ASK) modulation while simultaneously harvesting energy from the reader's field. HDX mode alternates between charging from the reader's continuous RF field and transmitting data bursts when the field is briefly interrupted, enabling longer read ranges at the cost of slower transaction times.

The chip contains 512 bits (64 bytes) of user-programmable EEPROM, structured to accommodate animal identification codes and supplementary data fields as defined by ISO 11785. Memory is organized to support the 64-bit unique ID required by the standard, with additional space for country codes, manufacturer data, and application-specific payloads. Password-protected access mechanisms prevent unauthorized read or write operations, enforcing field-level security during initialization and updates. The EM Microelectronic implementation uses inductive coupling for power and data transfer, with on-chip rectification and voltage regulation to drive the logic and EEPROM write cycles across industrial temperature ranges.

The EM4543 is deployed extensively in animal identification systems globally, embedded in glass capsule transponders for subcutaneous implantation in livestock, pets, and wildlife. Its dual FDX-B/HDX support ensures compatibility with multi-standard readers used by veterinary clinics, border control points, and research facilities. The chip ships in 2×12 mm and 3×13 mm glass ampoules for injectable form factors, as well as in ear tags and bolus tags for ruminants.

In access control, the EM4543 appears in key fobs, cards, and wristbands where LF frequency penetration through water, metal, or biological tissue is required. Its read/write capability allows credential updates in the field without tag replacement. Asset tracking deployments leverage the 512-bit memory for storing maintenance records, ownership chains, or batch identifiers on industrial containers, tooling, and reusable transport items. The chip's password protection differentiates it from read-only alternatives like the EM4100, making it suitable for applications requiring secure field updates. Compared to higher-memory LF ICs such as the EM4450, the EM4543 offers a cost-optimized balance for ISO 11784/85 compliance.

Programming the EM4543 requires a 125 kHz LF reader/writer capable of ISO 11785 command sets. Both FDX-B and HDX mode selection must match the reader configuration; multi-protocol readers typically auto-detect the mode on inventory. Password authentication is mandatory before write operations: the chip enforces a 32-bit password that must be transmitted before any memory modification commands. If the password is lost or incorrectly set during initialization, the EEPROM becomes permanently locked, so password management procedures are critical during provisioning.

Memory layout follows ISO 11785 structure: the first 64 bits encode the animal ID (country code, species flag, and unique number), with remaining bytes available for user data. Write operations are performed in blocks, and EEPROM endurance is typically rated for 100,000 cycles per block. Verify each write with a readback cycle, as undervoltage during write can corrupt data without error feedback. Reader antenna tuning is essential for reliable operation; detuning due to proximity to metal or liquids will reduce write range below read range. The EM4543 is compatible with readers designed for FDX-B / ISO 11784/5 standards. For applications requiring backward compatibility with EM4x00-series read-only tags, ensure the reader firmware supports mixed-tag inventories. Integrators migrating from the EM4200 will need to implement password handling and block-write logic not present in read-only workflows.

The EM4543 is available from EM Microelectronic through authorized distributors serving the animal ID and industrial RFID markets. Pre-programmed glass transponders (injectables) are typically sourced from inlay converters and integrators specializing in veterinary applications; expect MOQs of 500–1,000 units for custom programming and packaging. Bare die and wafer-level supply are reserved for high-volume OEMs embedding tags in proprietary housings.

When specifying, confirm whether your application requires FDX-B-only, HDX-only, or dual-mode support; some low-cost readers support only one mode. Clarify password provisioning: suppliers can pre-program passwords or ship tags in open (default password) state. Lead times for programmed transponders range from 4–8 weeks, longer for custom antenna tuning or encapsulation. For access control, cross-shop against the EM4205 / EM4305 if ISO 11784/85 compliance is not mandatory, as the 4x05 series offers similar memory and broader reader compatibility. In animal ID, compare the EM4550 if larger memory (1024 bits) is required. Ask suppliers for sample readers that support both FDX-B and HDX to validate interoperability before committing to volume orders. Ensure EEPROM data retention specs (typically 10 years minimum) meet regulatory requirements for your jurisdiction.