NCD1015M Datasheet, PDF (4/13 Pages) IXYS Corporation – Sequential Power & Data Transmission (HDX)

INTEGRATED CIRCUITS DIVISION
NCD1015M
3. Application Information
NCD1015M is designed to be used in a complete RFID HDX. For the RFID front-end to operate, only one inductor is
needed, to operate as an antenna.
Figure 1 shows the NCD1015M and the connections with the external component. NU1 and NU2 pins are not used
for the final application. Typical value for inductor “L” = 2.41mH. It is important to consider that the inductor has a
parasitic capacitance itself, which adds to the HF capacitor modifying the resonant frequency of the tank.
Figure 1: Application Diagram
V_DD
NU2
NU1
C_L C_R
GND
L
HF
4. Functional Overview and Description
4.1 Power Transfer
Power transfer to the tag is accomplished by radio frequency through coupling antennas in the transponder and the
reader. The reader and transponder operate in a sequential mode with time-separated power and data transmission
cycles. The RF operating field supplies power at the beginning of the request from the reader to the HDX transponder.
During the charge (or powering phase) of between 15 and typically 50 ms the reader generates an electromagnetic
field with a frequency of 134.2 kHz. The resonant circuit of the transponder is energized and the induced voltage is
rectified by the integrated circuit to charge the capacitor C_L. The transponder detects the end of the charge burst
(EOB) and transmits data using Frequency Shift Keying (FSK), utilizing the energy stored in the capacitor C_L. The
charge phase is followed directly by the read phase.
Figure 2: Charge and Read Phase - Voltage at the Reader’s Exciter and Transponder Coil
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PRELIMINARY
R00A