The ATA5577 is a flexible LF RFID chip and is Microchip's high runner with state-of-the-art performance, including distance. This device works perfectly with antennas of different sizes and quality factors. The ATA5577 also features on-chip capacitors trimmed to ±3%, which increases the accuracy of the tag's center frequency significantly. The patented AFE register extends the flexibility and performance even more. The analog behavior of the complete tag can be tuned through the air interface to the best performance by means of this register. Every ATA5577 in the world is unique, with a factory programmed UID (uniqe ID) that cannot be changed. This UID may be used as part of an overall security concept or it can be used as a given serial number copied into the standard user memory. The chip may have to be locked.