Description:
> TK4100 is a CMOS integrated circuit for use in 125KHz read only RFID card.
It is compatible with EM format.
Features:
> 64 bit memory array laser programmable
> Several options of data rate and coding available
> On chip resonance capacitor
> On chip voltage limiter
> Full wave rectifier on chip
> Large modulation depth due to a low impedance modulation device
> Operating frequency 100-150 KHz
> Very small chip size convient for implantation
> Very low power consumption
Operation:
Menchester modeulation coding (Type code, data rate is RF/64). Only if the chip produce at both ends of extermal coil induced voltage >=3.5Vpp and the clock rate is 125Khz , it will start working.

At the proximity card moment, the mobile payment or perhaps in the NFC for the mainstream, as mentioned above the NFC cellphones, it's going to just NFC chip nested on a mobile phone, the completion of payment business is founded on the telephone itself. But that many users worry about security problems, when the user change cellular phone, how applications running within the previously held in the cellphone is an issue to resolve, additionally, if you need to involve in terminals, is increased impact level, promote the problem isn't small, NFC terminal popularity will directly impact on the creation of mobile payment business.