An RFID reader module specification varies depending on the frequency band (Low Frequency, High Frequency, or Ultra-High Frequency), with the popular RC522 RFID Module (High Frequency) and EM-18 RFID Reader (Low Frequency) representing common embedded choices.
| • Core IC | NXP MFRC522 |
| • Operating Frequency | 13.56 MHz |
| • Operating Voltage | 2.5V – 3.3V (Note: Logic pins are often 5V tolerant on some breakout boards, but VCC must stay at 3.3V) |
| • Operating Current | 13 mA – 26 mA (Sleep mode: <80 µA) |
| • Read/Write Distance | Up to 50 mm (5 cm) |
| • Communication Interfaces | SPI, I2C, UART |
| • Supported Card Types | MIFARE1 S50, S70, Ultralight, Pro, and DESFire |
| • Operating Temperature | -20°C to +80°C |
| Deep-Dive | Popular EM-18 (LF 125 kHz) Specifications |
| • Operating Frequency | 125 kHz |
| • Operating Voltage | +5V DC |
| • Operating Current | ~50 mA |
| • Read Distance | Up to 10 cm |
| • Output Formats | UART (9600 bps, 8N1) and optional Wiegand output |
| • Antenna | Integrated on-chip PCB antenna |