EM4205/4305 is a CMOS integrated circuit intended for use in Read/Write RF transponders. 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 option.
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.