ATA5577M3 vs EM4100

Compare Microchip ATA5577M3 rewritable 330-bit LF RFID with EM4100 read-only 64-bit transponder. Memory, security, multi-protocol support, and application guide.

Side-by-side specs

Frequency

ATA5577M3: 125 kHz
EM4100: 100-150 kHz (typical 125 kHz)

Protocol

ATA5577M3: EM4100, EM4102, T5557, Hitag, Indala, and other LF formats
EM4100: Proprietary EM4100 format, Manchester/Biphase/PSK encoding

Memory

ATA5577M3: 363 bits total (330 bits user programmable)
EM4100: 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

ATA5577M3: RF (contactless)
EM4100: RF (contactless), no digital interface

Temp Range

ATA5577M3: -40°C to +85°C
EM4100: -40°C to +85°C

Form Factor

ATA5577M3: Wafer, SO8, TSSOP8
EM4100: 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

ATA5577M3: 32-bit password protection for read/write operations
EM4100: None (read-only, no encryption or authentication)

Spec	ATA5577M3	EM4100
Frequency	125 kHz	100-150 kHz (typical 125 kHz)
Protocol	EM4100, EM4102, T5557, Hitag, Indala, and other LF formats	Proprietary EM4100 format, Manchester/Biphase/PSK encoding
Memory	363 bits total (330 bits user programmable)	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)	RF (contactless), no digital interface
Temp Range	-40°C to +85°C	-40°C to +85°C
Form Factor	Wafer, SO8, TSSOP8	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	32-bit password protection for read/write operations	None (read-only, no encryption or authentication)

Verdict

Choose the ATA5577M3 if you need field-programmable, rewritable RFID tags operating at 125 kHz with multi-protocol flexibility. This chip offers 363 bits total memory with 330 bits user-programmable, allowing you to store and update data after deployment. The ATA5577M3 supports EM4100, EM4102, T5557, Hitag, Indala, and other LF formats, making it suitable for applications requiring protocol emulation or migration between different access control systems. It includes 32-bit password protection for both read and write operations, providing basic security for controlling who can modify or access tag data. This makes it ideal for applications like animal tracking, access control systems requiring periodic updates, inventory management with changing data, or situations where you need one tag type to work across multiple reader infrastructures. The rewritability allows you to provision tags in the field, recycle tags for different users, or update stored information without replacing hardware. Choose the EM4100 if you need simple, low-cost, read-only identification tags for basic access control or identification applications at 125 kHz. This chip contains 64 bits total, factory laser-programmed and permanently read-only, structured as 9 header bits, 8 version/customer ID bits, 32 data bits, plus error-checking parity bits (10 row, 4 column) and 1 stop bit. The EM4100 uses proprietary Manchester, Biphase, or PSK encoding and operates across 100-150 kHz with 125 kHz typical. It offers no security features—no encryption, authentication, or write protection—making it purely an identification device. The EM4100 is the industry standard for basic proximity cards in access control, suitable for applications like employee badges, hotel key cards, parking systems, or any scenario where you need permanent, unchangeable ID numbers at the lowest cost. Its read-only nature prevents tampering or accidental overwrites, and its widespread adoption ensures compatibility with countless existing 125 kHz readers worldwide.

FAQ

Can the ATA5577M3 emulate EM4100 tags?

Yes, the ATA5577M3 explicitly supports EM4100 and EM4102 formats among its multi-protocol capabilities, allowing it to emulate EM4100 tags while also offering rewritable memory that the original EM4100 lacks.

What is the memory difference between ATA5577M3 and EM4100?

The ATA5577M3 provides 330 bits of user-programmable memory out of 363 bits total, while the EM4100 has only 64 bits total (40 bits usable data after headers and parity) that are factory-programmed and read-only.

Does the EM4100 have any security features?

No, the EM4100 has no security features—no encryption, no authentication, and no write protection. It is a read-only tag transmitting its fixed ID openly, whereas the ATA5577M3 offers 32-bit password protection for read and write operations.

Sourcing ATA5577M3 or EM4100 in volume?

Roxtron builds custom RFID and NFC products around both ATA5577M3 and EM4100. Tell us your project — quantities, form factor, timeline — and we'll come back within 24 hours with pricing and lead times.