How to Choose an RFID Tag IC
A Systematic Selection Guide
A systematic approach to selecting the right RFID tag IC based on memory, sensitivity, frequency, and application requirements.
How to Choose an RFID Tag
Selecting the wrong RFID tag is the most common cause of pilot failures. The right choice depends on the tagged substrate, operating environment, required read range, memory needs, and volume economics.
Selection Criteria Framework
Work through five criteria in order:
- Frequency — Determined by application physics (see RFID Frequency Bands Explained). UHF for supply chain; HF for payments and NFC; LF for animal ID.
- Substrate — Metal detunes standard inlay antennas; liquids absorb UHF energy. Both require specialty tags.
- Read range — Drives antenna size, tag sensitivity, and reader power. Use the Read Range Calculator.
- Memory — EPC length, user memory, and lock requirements (see RFID Tag Memory Planning).
- IC selection — Different tag ICs offer different sensitivity, die size, and feature sets.
IC Comparison (UHF Gen 2)
| IC | Vendor | Sensitivity | Typical Range | Unique Feature |
|---|---|---|---|---|
| Impinj M730 | Impinj | −20 dBm | 7–9 m | EnduroMode (high writes) |
| Impinj M775 | Impinj | −21 dBm | 8–10 m | AutoTune, integrated crypto |
| NXP UCODE 9 | NXP | −22 dBm | 8–11 m | Untraceable, 32B user mem |
| NXP UCODE DNA | NXP | −21 dBm | 7–9 m | AES-128 mutual auth |
| EM4325 | EM Microelectronic | −18 dBm | 5–7 m | Semi-passive, sensor bridge |
| Alien Higgs-9 | Alien Technology | −22 dBm | 9–11 m | Ultra-small die, best sensitivity |
More negative sensitivity values indicate better performance: a tag at −22 dBm activates with less reader power and at longer distance.
Environment Considerations
| Environment | Tag Type | Key Requirement |
|---|---|---|
| Metal assets (tools, shelving) | On-metal / PCB tag | Spacer layer to detune antenna |
| Liquids / food | Liquid-tolerant inlay | HF, or UHF with tuned antenna geometry |
| Outdoor UV/rain | IP67+ enclosure | UV-stable housing, extended temp range |
| High-temp (>85 °C) | Industrial tag | Rated IC + adhesive up to 150 °C |
| Laundry / steam | Laundry tag | Woven antenna, wash-cycle rating |
| Clean-room (pharma) | Lab tag | ESD-safe, autoclavable variants |
Memory Needs
Evaluate before selecting an IC:
- EPC bank: 96 bits is standard; 128 or 240 bits if encoding long serial numbers or GIAI.
- User memory: Required for gs1-digital-link/" class="glossary-term-link" data-term="GS1 Digital Link" data-definition="Web URI format for GS1 identifiers." data-category="Integration">GS1 Digital Link payloads, sensor data, or custom fields. Ranges from 0 to 512 bytes by IC.
- TID: Always present; use for anti-counterfeiting fingerprinting.
Use the Memory Planner to lay out your data before committing to an IC.
Use the RFID Tag Selector to filter by all criteria simultaneously — substrate, frequency, memory, and read range — and compare shortlisted tags side by side.
See also: Impinj Tag IC Generations Compared, NXP UCODE Family Guide.
Frequently Asked Questions
The four primary factors are: frequency band (matching your application environment and read range requirements), memory configuration (EPC size and user memory for ancillary data), sensitivity (minimum reader power needed to activate the tag, measured in dBm), and protocol features (anti-collision performance, security, sensor interfaces). Cost per tag at your deployment volume is a secondary constraint.
Standard GS1 SGTIN-96 encoding requires a 96-bit EPC bank, which is sufficient for most retail and supply chain applications. If you need GIAI, SSCC, or proprietary encodings that exceed 96 bits, select a tag with 128-bit or larger EPC memory. Impinj M700 series offers configurable EPC sizes up to 480 bits for applications requiring extended identifiers.
Yes — the material your tag attaches to significantly impacts performance. Standard UHF dipole tags detune and lose range when applied to metals or liquids. For metal surfaces, use on-metal (PCB or foam-core) tags designed with ground planes. For items containing liquids, HF (13.56 MHz) inductive tags are more tolerant, or select UHF tags specifically validated for wet environments.
Tag sensitivity (read sensitivity) is the minimum RF power, measured in dBm, required to activate and power the tag IC. Lower (more negative) dBm values indicate better sensitivity — a tag at -22 dBm activates with less power than one at -18 dBm, resulting in longer read range for the same reader output power. Impinj M730 and Alien Higgs-9 at -22 dBm represent current high-sensitivity benchmarks.
Our guides cover a range of experience levels. Getting Started guides introduce RFID fundamentals. Implementation guides help engineers design RFID solutions for specific industries. Advanced guides cover topics like dense reader mode, anti-collision algorithms, and EPC encoding schemes.
Most getting-started guides require only a basic UHF RFID reader (such as the Impinj Speedway or ThingMagic M6e) and a few sample tags. Some guides reference desktop USB readers for development. All hardware requirements are listed at the beginning of each guide.