MLX90130
13.56MHz RFID Transceiver
3901090130
Page 30 of 37
Jan-2014
Rev. 004
11 Application Information
11.1 External Antenna network
RF communication performance depends on the external system antenna network and resonance conditions.
The antenna matching of the MLX90130 is reduced to a minimal component count, composed of two serial
capacitors Cs and one parallel capacitor Cp. A parallel resistor Rp can also be added to adjust the antenna
damping thus reducing detuning effect provoked by the presence of TAGs or Readers in front of the
MLX90130. Two serial resistors R
RX
have to be adjusted in order to avoid entering the clamping region (see
below). Finally, depending on EMC constraints, an EMI filter can be added to reduce the emission
of harmonics generated by the square wave at the outputs TX1 and TX2.
Figure below gives an example of the external matching network to connect the antenna. For more
information, please refer to the application note
AN1_MLX90130_32_AntennaDesignGuidelines
available on
the Melexis website.
MLX90130
R
RX
R
RX
C
S
C
S
C
P
R
P
Lo
op
An
te
nn
a
L
EMI
L
EMI
C
EMI
C
EMI
R
X1
R
X2
T
X1
T
X2
Figure 14: External antenna matching network example
11.2 Application schematic
MLX90130
N
C
N
C
N
C
N
C
N
C
N
C
N
C
N
C
VDD
IRQ
IN
VDC
RX1
RX2
GND_RX
NC
NC
GND_DIG
XIN
XOUT
GND_TX
VDD_TX
TX1
TX2
NC
IR
Q
O
U
T
S
S
M
IS
O
M
O
S
I
S
C
K
S
S
I_
0
S
S
I_
1
N
C
27.12MHz
VDD
Example of
EMI Filter
Matching
Antenna
V
D
D
_T
X
VDD
Application
Microcontroller
Figure 15: MLX90130 application schematic in SPI mode
