EM4205/ EM4305- LF Animal & Access ICs

512 bit Read/Write multi-purpose low-frequency contactless identification device

General Description

EM4205/4305 is a CMOS integrated circuit intended for use in electronic Read/Write RF transponders. It is suitable for low cost solutions like animal tagging applications. The IC communication protocol is compatible with the EM4469/4569 family.

The main difference between the EM4205 and EM4305 is that:

  • EM4305 are bumped with enlarged pads for the two coil inputs. The enlarged bumped pads of the EM4305 transponder are intended for direct antenna connection avoiding the need of a module.
  • EM4305 offers a 330pF resonant capacitor version.

The IC is powered by picking up energy from a continuous 125 kHz magnetic field via an external coil, which together with the integrated capacitor form a resonant circuit. The IC reads out data from its internal EEPROM and sends it out by switching on and off a resistive load in parallel to the coil using a large modulation index. Commands and EEPROM data updates can be executed by 100% AM modulation of the 125 kHz magnetic field.

The EM4205/4305 supports bi-phase and Manchester data encodings. The EM4205/4305 operating modes are stored in the EEPROM configuration word. All EEPROM words can be write-protected by setting protection bits. The IC contains a factory programmed 32 bit unique identifier number (UID).


  • Animal Identification according to ISO FDX-B
  • Pigeon races standard
  • Waste management standard (BDE)
  • Access Control
  • Industrial


  • 512 bit EEPROM organized in 16 words of 32 bit
  • 32 bit unique identifier (UID)
  • 32 bit Password read and write protection
  • ISO 11784 / 11785 Standard Compliant
  • Lock feature converts EEPROM words into Read Only
  • Two data encodings: Manchester and Bi-phase
  • Multi-purpose data rate: 8, 16, 32, 40 and 64 RF clocks
  • Reader Talk First feature
  • Compatible with EM4469/EM4569 communication protocol
  • 100 to 150 kHz frequency range
  • On-chip rectifier and voltage limiter
  • No external supply buffer capacitor needed
  • -40°C to +85°C temperature range
  • Very low power consumption
  • Enlarged bumped pads (200 μm x 400 μm) for direct connection of coil (EM4305)
  • EM4205: 2 resonant capacitor versions 210pF or 250pF selectable by mask option. The resonant capacitor can be trimmed, at factory level, to offer accuracy on the tolerance of 3%.
  • EM4305: 3 resonant capacitor versions 210pF, 250pF or 330pF selectable by mask option
  • Available in plastic extremely thin small outline package; 2 terminals; body 1.1 * 1.4 * 0.46 mm
EM4205/4305 Factsheet (381.96 KB)381.96 KB
EM4205/4305 Datasheet (671.63 KB)671.63 KB
Part numberStockMOQPrice
EM4305V7WS6EAvailable on demand88'000$0.15Order now
EM4305V8WS6EAvailable on demand88'000$0.15Order now
EM4305V2WS11EAvailable on demand--Order now
EM4305V3WS11EAvailable on demand--Order now

Contact usGeneral inquiries