EM4100
The EM Microelectronic EM4100 is an LF 125 kHz RFID tag IC, with 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, operating at 100-150 kHz (typical 125 kHz), under Proprietary EM4100 format Manchester/Biphase/PSK encoding.
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
Standards & Compliance
Frequently Asked Questions
What frequency does the EM4100 RFID chip operate at?
The EM4100 operates at 125 kHz (100-150 kHz range), a low-frequency RFID standard commonly used for proximity access control cards and asset tags.
Can the EM4100 memory be reprogrammed or written to?
No, the EM4100 is factory laser-programmed and read-only. The 64-bit memory (including 32 data bits and 8-bit customer ID) cannot be modified after manufacturing.
Does the EM4100 require a battery?
No, the EM4100 is a fully passive transponder powered entirely by the RF field from the reader. It integrates a rectifier and voltage limiter to harvest energy from the 125 kHz carrier.
What encoding does the EM4100 use for data transmission?
The EM4100 supports Manchester, Biphase, or PSK encoding with configurable data rates of 64, 32, or 16 RF periods per bit for load modulation communication.
What are the typical applications for EM4100 chips?
EM4100 chips are widely used in low-cost proximity access cards, asset tags, animal identification, and legacy RFID systems where simple read-only unique IDs are sufficient.
Does the EM4100 support encryption or security features?
No, the EM4100 has no built-in security, encryption, or authentication. It is a simple read-only tag designed for applications where unique identification rather than security is the priority.
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