EM4100
Read-only 64-bit transponder, industry standard for access cards
Full Specifications
| Manufacturer | EM Microelectronic |
|---|---|
| Frequency Category | LF 125 kHz |
| Frequency | 100-150 kHz (typical 125 kHz) |
| Protocol | Proprietary EM4100 format, Manchester/Biphase/PSK encoding |
| Memory | 64 bits total (factory laser-programmed, read-only): 9 header bits + 8 version/customer ID bits + 32 data bits + 10 row parity bits + 4 column parity bits + 1 stop bit |
| Interface | RF (contactless), no digital interface |
| Temperature Range | -40°C to +85°C |
| Form Factor | Die (1016 × 1041 μm), CID package (8.5 × 4.0 mm, 2 pins), PCB package (8.0 × 4.0 mm, 2 pins), wafer/sawn wafer/sticky tape |
| Security | None (read-only, no encryption or authentication) |
Engineering Brief
The EM4100 is a classic 125 kHz read-only RFID transponder IC with 64 bits of factory-programmed memory. It is powered entirely by the reader's RF field (no battery) and uses load modulation to transmit data back at configurable rates (64/32/16 RF periods per bit) with Manchester, Biphase, or PSK encoding. The chip integrates a full-wave rectifier, 74 pF resonance capacitor, 120 pF supply capacitor, and voltage limiter, requiring only an external coil (~21.9 mH at 125 kHz). Its simple architecture, tiny die size, and very low power consumption make it ideal for disposable access cards, asset tags, and legacy RFID systems where unique read-only IDs suffice.
Typical Applications
- Access control cards and badges
- Industrial transponders and asset tracking
- Logistics automation and inventory management
- Anti-counterfeiting tags
- Animal identification implants
- Low-cost proximity cards
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