The ATA5577 (T5577 for short) chip from Microchip (formerly Atmel) is a very poular Low Frequency (125KHz) card. It is compatible with Microchip's T5557/ATA5567 and a replacement for the e5551/T5551 in many common operations. T5577 has a frequency of 125KHz but its strength comes from the fact it is..