2451ZA Datasheet, PDF (4/8 Pages) Gennum Corporation – Protects one high speed data line

PROTECTION PRODUCTS
Applications Information
ESD Protection of NFC Interfaces
The Near Field Communication (NFC) antenna is
usually connected to the NFC controller IC via contact
points on the phone. These contact points are user
accessable and therefore may be subjected to ESD
strikes. External protection (TVS) devices should be
placed between the antenna and the NFC chip inter-
face. The working voltage of the TVS should be high
enough as not to clip the NFC signal. Additionally, the
capacitance of the device should be minimized in order
to avoid harmonic distortion of the RF signal.
RClamp2451ZA meets these requirements and also
features extremely low dynamic resistance (<0.1
Ohms) resulting in low ESD clamping voltage. The low
dynamic resistance also helps insure protection for
Schottky diodes that may be used in the NFC circuit.
RClamp2451ZA is designed to work on NFC circuits
with AC signals as high as 24V. An example protection
ciruit using RClamp2451ZA is shown below in Figure 1.
RClamp2451ZA
RX+
RX-
TX+ _{EMI Filter}
Ckt
Antenna
Matching
Ckt
NFC
Controller
REC
TX-
EMI Filter
Ckt
Antenna
Matching
Ckt
© 2014 Semtech Corporation
R
C
Figure 1 - NFC Protection Example
4
Antenna +
RClamp 2451ZA
GND
RClamp 2451ZA
Antenna -
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