mfrc531 NXP Semiconductors, mfrc531 Datasheet - Page 30

• Manufacturer Part Number: mfrc531
• Description: Iso/iec 14443 Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
MFRC531_34
Product data sheet
PUBLIC
9.9.2 Antenna operating distance versus power consumption
9.9.3 Antenna driver output source resistance
Table 25.
Using different antenna matching circuits (by varying the supply voltage on the antenna
driver supply pin TVDD), it is possible to find the trade-off between maximum effective
operating distance and power consumption. Different antenna matching circuits are
described in the Application note “MIFARE Design of MFRC500 Matching Circuit and
Antennas”.
The output source conductance of pins TX1 and TX2 can be adjusted between 1 Ω and
100 Ω using the CwConductance register GsCfgCW[5:0] bits.
The output source conductance of pins TX1 and TX2 during the modulation phase can be
adjusted between 1 Ω and 100 Ω using the ModConductance register GsCfgMod[5:0] bits.
The values are relative to the reference resistance (R
production test and stored in the MFRC531 EEPROM. It can be read from the product
information field (see
in
TxControl register configuration
TX2RFEn
0
1
1
1
1
1
1
1
1
1
1
1
1
Section 13.3.3 on page
Pin TX2 configurations
FORCE100ASK
X
0
0
0
0
0
0
1
1
1
1
1
1
Section 9.2.1 on page
Rev. 3.4 — 26 January 2010
92.
TX2CW
X
0
0
0
0
1
1
0
0
0
0
1
1
056634
TX2Inv
X
0
0
1
1
0
1
0
0
1
1
0
1
13). The electrical specification can be found
Envelope
X
0
1
0
1
X
X
0
1
0
1
X
X
S(ref)
) which is measured during the
TX2 signal
LOW
13.56 MHz carrier frequency
modulated
13.56 MHz carrier frequency
13.56 MHz carrier frequency
modulated, 180° phase-shift
relative to TX1
13.56 MHz carrier frequency,
180° phase-shift relative to TX1
13.56 MHz carrier frequency
13.56 MHz carrier frequency,
180° phase-shift relative to TX1
LOW
13.56 MHz carrier frequency
HIGH
13.56 MHz carrier frequency,
180° phase-shift relative to TX1
13.56 MHz carrier frequency
13.56 MHz carrier frequency,
180° phase-shift relative to TX1
ISO/IEC 14443 reader IC
MFRC531
© NXP B.V. 2010. All rights reserved.
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