LF 125 kHzEM Microelectronic

EM4205 / EM4305

512-bit R/W multi-purpose transponder

Official Datasheet ↗
Frequency
125 kHz (100 to 150 kHz range)
Protocol
ISO 11784 / 11785 Standard Compliant, compatible with EM4469/EM4569 communication protocol
Memory
512 bit EEPROM organized in 16 words of 32 bit (288 bits user free in words 5-13), 32 bit unique identifier (UID), 32 bit password
Interface
RF (contactless)
Temp Range
-40°C to +85°C
Form Factor
EMDFN02 (2.2 x 1.78 x 0.76 mm), EMDFN403 (1.1 x 1.4 x 0.46 mm), die/wafer form available

Full Specifications

ManufacturerEM Microelectronic
Frequency CategoryLF 125 kHz
Frequency125 kHz (100 to 150 kHz range)
ProtocolISO 11784 / 11785 Standard Compliant, compatible with EM4469/EM4569 communication protocol
Memory512 bit EEPROM organized in 16 words of 32 bit (288 bits user free in words 5-13), 32 bit unique identifier (UID), 32 bit password
InterfaceRF (contactless)
Temperature Range-40°C to +85°C
Form FactorEMDFN02 (2.2 x 1.78 x 0.76 mm), EMDFN403 (1.1 x 1.4 x 0.46 mm), die/wafer form available
Security32 bit password read and write protection, lock feature converts EEPROM words into read-only

Engineering Brief

The EM4205/4305 is a 125 kHz LF read/write RFID transponder with 512 bits of EEPROM organized as 16×32-bit words, compliant with ISO 11784/11785 for animal identification. It features a factory-programmed 32-bit UID, 32-bit password protection, configurable data rates (RF/8 to RF/64), and supports both Manchester and Bi-phase encoding. The chip includes on-chip rectifier, voltage limiter, integrated resonant capacitor (210pF, 250pF, or 330pF versions), and operates without external supply buffer capacitor across industrial temperature range.

Typical Applications

  • Animal identification (ISO FDX-B)
  • Pigeon races standard
  • Waste management standard (BDE)
  • Access control
  • Industrial applications
  • Livestock tracking

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