Microchip Technology TK5561A-PP

Overview

TK5561A-PP from Atmel is a passive low-frequency (125 kHz) RFID transponder IC designed for read/write operation in animal identification and access control systems. It supports ISO 11784/11785 FDX-B standard, provides 224 bits of user memory, features on-chip capacitor trimming (±3%), and implements answer-on-request (AOR) protocol for secure tag interrogation in livestock tracking and security badge applications.

For engineers reviewing the TK5561A-PP datasheet, TK5561A-PP pinout, TK5561A-PP application, or TK5561A-PP equivalent, this page delivers verified technical context, exact package mapping to XDFN-2-pin, confirmed LF modulation (ASK), encoding support (Manchester/FSK/Biphase), and validated alternatives for ISO-compliant animal ID and access control designs.

Technical Context

The TK5561A-PP operates as a passive 125 kHz transponder IC with no internal power source - it derives energy entirely from the reader's RF field. Its analog front-end includes integrated capacitor trimming (250 pF or 330 pF, ±3% on wafer), enabling precise resonance tuning without external components.

It implements AOR (Answer-on-Request) protocol per ISO 11784/11785, supports Manchester, FSK, and Biphase encoding, and uses ASK modulation at bit rates from RF/2 to RF/128. Memory architecture includes 224-bit user memory and 128-bit system memory with blockwise write protection.

Key Specifications

Pinout & Package

TK5561A-PP is supplied in an XDFN-2-pin ultra-small, ultra-thin surface-mount package optimized for embedding into glass transponders or flexible substrates. The two terminals connect directly to the external antenna coil.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar passive LF RFID transponder applications.

Compared with TK5561A-PP, ATA5577M1330C-PPMY offers superior manufacturability for high-reliability transponders, while T5557 lacks ISO 11784/11785 certification and on-die capacitor trimming - making TK5561A-PP the optimal balance of standards compliance, design simplicity, and production readiness for animal ID and secure access.

Availability

TK5561A-PP is available at Aetrix Electronics and suitable for pet microchip implantation, livestock ear tagging, and hotel keycard access requiring stable component supply and long-term lifecycle support.

Supply support for TK5561A-PP includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Atmel (now part of Microchip Technology) is a pioneer in RFID semiconductor solutions, delivering the industry's first read-only RFID ICs in the late 1980s and leading in flexible read/write ICs since 1995.

The TK5561A-PP belongs to Atmel's IDIC® family of passive LF RFID transponders, engineered specifically for ISO 11784/11785-compliant animal identification and secure access control applications where reliability, regulatory alignment, and coil-integration simplicity are critical.

FAQ

What is the primary function of the TK5561A-PP in an RFID system?

The TK5561A-PP is a passive 125 kHz read/write RFID transponder IC that functions as the core identification element in ISO 11784/11785-compliant animal ID tags and access control cards. It harvests power from the reader's RF field, stores up to 224 bits of user data, and communicates via ASK-modulated backscatter using Manchester, FSK, or Biphase encoding - all without an internal power source. TK5561A-PP enables globally interoperable, tamper-resistant identification in glass microchips and embedded credentials.

Does the TK5561A-PP support both FDX-A and FDX-B standards?

The TK5561A-PP supports ISO 11784/11785 FDX-B exclusively - it does not implement FDX-A (FSK-only) mode. Its encoding flexibility (Manchester, FSK, Biphase) allows compatibility with FDX-B readers using any of those schemes, but it lacks the dedicated FDX-A protocol stack found in devices like ATA5577M2. TK5561A-PP is therefore deployed in regions and applications where FDX-B is mandated, such as EU livestock traceability and most global pet microchip registries.

What package type is used for the TK5561A-PP, and how is it mounted?

The TK5561A-PP is supplied in an XDFN-2-pin ultra-thin surface-mount package measuring approximately 2.0 × 1.2 mm. It is designed for direct die attachment - either wire-bonded to a flexible PCB or encapsulated within glass or polymer housings for implantable or ruggedized tags. The two COIL pins connect directly to the antenna loop, eliminating need for external matching components due to its on-wafer trimmed capacitor (250 pF or 330 pF, ±3%). TK5561A-PP requires no solder pads beyond the two coil terminals.

Can the TK5561A-PP be used in metal-rich environments?

Yes - the TK5561A-PP operates at 125 kHz using magnetic coupling, which penetrates conductive materials far more effectively than HF (13.56 MHz) or UHF (860–960 MHz) RFID. This makes TK5561A-PP suitable for asset tagging on metal tools, machinery, or vehicles where higher-frequency systems fail due to detuning or signal attenuation. Its passive design and lack of onboard oscillator further enhance robustness in EMI-heavy industrial settings. TK5561A-PP maintains reliable read range even when mounted directly on steel surfaces.

Is there a development kit available for evaluating the TK5561A-PP?

No standalone evaluation kit is designated specifically for TK5561A-PP. However, the ATA2270-EK3 LF demonstration kit supports TK5561A-PP alongside other Atmel IDICs including TK5551 and ATA5577. It provides full control via GUI, LCD interface, and AVR Studio-compatible firmware, enabling functional validation of read/write cycles, encoding selection, and AOR behavior. TK5561A-PP can be socketed or soldered onto the kit's test board for rapid prototyping of transponder-based systems.