Ci521 — 13.56 MHz Contactless Reader IC Supporting ISO/IEC 14443A/B
11/25/2025
The Ci521 is a highly integrated 13.56 MHz contactless reader chip supporting ISO/IEC 14443 A/B.
Internal transmitter directly drives the antenna; receiver provides robust demodulation/decoding; digital section handles full ISO/IEC 14443A/B framing, parity, and CRC.
Host interface: SPI (up to 10 Mbit/s).
Key Features
Highly integrated analog circuitry
Buffered output drivers, minimal external components
Typical operating distance ~50 mm (antenna-dependent)
Up to 848 kBd high-speed communication
64-byte TX/RX FIFO
Flexible interrupts, hard/soft power-down, programmable timer
Internal oscillator for 27.12 MHz quartz
2.3–3.6 V supply
Integrated CRC co-processor
.png)
.png)
