The T5577 (also known as ATA5577) is a low-frequency (LF) RFID chip​ widely used in access control cards, hotel keys, and identification systems. Here is a detailed introduction in English.

1. Basic Definition

The T5577 is a multifunctional contactless read/write IC​ manufactured by Atmel (now part of Microchip). It operates at the 125 kHz​ frequency band and is known for its rewritable​ and configurable​ nature, making it a common choice for low-security RFID applications.

2. Key Technical Specifications

The chip includes a configuration block​ (Block 0) that allows it to emulate other 125 kHz protocols like EM4200 or TK4100, increasing its compatibility with existing readers.

3. Common Applications

• Access Control Systems: Office buildings, residential gates.
• Hotel Key Cards: Widely used as programmable key cards for door locks.
• Animal Identification: LF tags for livestock tracking.
• Industrial Automation: Process control and asset tagging.

4. Card Formats

The chip is typically embedded in standard card form factors:

• CR80 Cards​ (85.6 × 54 mm, standard credit card size)
• Key Fobs
• Sticker Tags​ or Coin Tags

5. Security Note

While T5577 supports a simple 8-bit password, it is considered a low-security​ RFID technology compared to modern 13.56 MHz (HF) chips like MIFARE or NFC. It is susceptible to cloning if not properly encrypted.

In summary, T5577 is a versatile and cost-effective solution for basic RFID tagging and access control where high security is not the primary requirement.