What Is the EM4405 RFID Chip?
The EM4405 is a low-frequency (LF) read/write RFID integrated circuit widely used in secure identification and industrial automation systems. Operating in the 100–150 kHz range, the EM4405 is designed for contactless transponders that require high reliability, data security, and EEPROM flexibility.
With 1 Kbit of configurable EEPROM, built-in security mechanisms, and minimal external component requirements, the EM4405 has become a proven solution for ticketing, access control, immobilizers, and prepaid systems.
This article provides a complete technical and application-level overview of the EM4405 RFID chip, going well beyond basic datasheet summaries.
EM4405 General Description
The EM4405 is a CMOS integrated circuit intended for electronic read/write RF transponders. It stores data in 1 Kbit of EEPROM, organized as 32 words × 32 bits, and supports multiple user-defined memory protection modes.
Each chip is uniquely identifiable thanks to factory laser-programmed ROM areas, making it suitable for applications where authentication and traceability are critical.
The EM4405 communicates with the reader by amplitude modulation (AM) of the RF field and requires only a tuned coil as an external component.
EM4405 Memory Architecture Explained
One of the strongest advantages of the EM4405 RFID chip is its highly configurable EEPROM structure.
EEPROM Organization
- Total Memory: 1 Kbit (1024 bits)
- Structure: 32 words × 32 bits
- User Configurable Areas:
- Read-only (locked)
- Write-inhibited
- Read-protected
- Free read/write area
This flexibility allows system designers to separate public data, secure data, and system control data on the same transponder.
Security Features of the EM4405 RFID Chip
32-Bit Password Protection
The EM4405 supports a 32-bit password used to secure:
- All write operations
- All read-protected memory areas
Key security characteristics:
- Password can be updated
- Password can never be read
- Prevents cloning and unauthorized modification
Unique Chip Identity
Each EM4405 contains:
- 32-bit Device Serial Number (Read-Only, Laser ROM)
- 32-bit Device Identification Code (Read-Only, Laser ROM)
These factory-programmed values ensure that no two chips are identical, enabling strong anti-counterfeiting and authentication schemes.
Communication and Data Transmission
The EM4405 uses LF RFID passive communication, meaning it draws power directly from the reader’s electromagnetic field.
Key Communication Characteristics
- Modulation: Amplitude Modulation (AM)
- Data Rates:
- 2 KBd (Opt64)
- 4 KBd (Opt32)
- Field Frequency: 100–150 kHz
This makes the EM4405 fully compatible with standard 125 kHz RFID readers used globally in access control and industrial systems.
Power Management and Reliability
The EM4405 is optimized for low power consumption and stable operation in harsh environments.
Integrated Power Features
- On-chip rectifier
- On-chip voltage limiter
- Power-On Reset (POR)
- EEPROM write voltage check
Because of its efficient design:
- No external buffer capacitor is required
- Only a coil and tuning capacitor are needed
- Ideal for small form-factor transponders
Environmental and Electrical Specifications
| Parameter | Specification |
|---|---|
| Operating Temperature | −40°C to +85°C |
| Field Frequency | 100–150 kHz |
| On-Chip Resonant Capacitor | 170 pF ± 2% |
| Power Supply | Fully passive |
| Package | Chip form (for mass production) |
These characteristics make the EM4405 suitable for automotive, industrial, and outdoor deployments.
EM4405 vs Other LF RFID Chips
Compared with basic LF read-only chips (such as EM4100 series), the EM4405 offers:
- Full read/write EEPROM
- Strong password-based security
- User-defined memory access control
- Higher flexibility for complex systems
It is often considered functionally compatible with EM4450-type applications, depending on system design.
Typical EM4405 RFID Applications
The EM4405 is widely used across industries that require secure, durable, and flexible LF RFID identification.
Common Use Cases
- Ticketing Systems
- Automotive Immobilizers (with rolling code systems)
- High-Security Hands-Free Access Control
- Industrial Automation with Portable Databases
- Manufacturing Automation
- Prepayment and Credit-Based Devices
Its ability to store dynamic data makes it especially valuable in systems where information must be updated throughout the product lifecycle.
Why Choose EM4405 for LF RFID Projects?
From an engineering and procurement perspective, the EM4405 offers:
- Proven LF RFID reliability
- Flexible memory configuration
- Strong security without complex hardware
- Minimal BOM cost
- Wide reader compatibility
- Long-term industrial stability
These advantages explain why the EM4405 remains relevant even as UHF and NFC technologies grow.
Conclusion
The EM4405 RFID chip is a mature, secure, and highly configurable low-frequency read/write transponder IC. With 1 Kbit EEPROM, password protection, unique serial identification, and minimal external component requirements, it is an excellent choice for access control, ticketing, industrial automation, and secure identification systems.
For businesses and system integrators looking for a cost-effective yet secure LF RFID solution, EM4405 continues to be a dependable industry standard.
About XIUCHENG RFID
XIUCHENG RFID provides EM4405-based RFID tags, cards, key fobs, and custom transponder solutions for industrial, automotive, and access control applications. We support chip selection, antenna tuning, encoding, and mass production.
Contact us to discuss your EM4405 RFID project requirements.
