
CLRC632_35
NXP B.V. 2009. All rights reserved.
Product data sheet
PUBLIC
Rev. 3.5 — 10 November 2009
073935
32 of 126
NXP Semiconductors
CLRC632
Multiple protocol contactless reader IC (MIFARE/I-CODE1)
9.9.2 Antenna operating distance versus power consumption
Using different antenna matching circuits (by varying the supply voltage on the antenna
driver supply pin TVDD), it is possible to nd 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”.
9.9.3 Antenna driver output source resistance
The output source conductance of pins TX1 and TX2 can be adjusted between 1
and
100
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
and 100 using the ModConductance register GsCfgMod[5:0] bits.
The values are relative to the reference resistance (RS(ref)) which is measured during the
production test and stored in the CLRC632 EEPROM. It can be read from the product
Table 27.
Pin TX2 congurations
TxControl register conguration
Envelope
TX2 signal
TX2RFEn
FORCE100ASK
TX2CW
TX2Inv
0X
X
LOW
1
0
13.56 MHz carrier frequency
modulated
1
0
1
13.56 MHz carrier frequency
1
0
1
0
13.56 MHz carrier frequency
modulated, 180
° phase-shift
relative to TX1
1
0
1
13.56 MHz carrier frequency,
180
° phase-shift relative to TX1
1
0
1
0
X
13.56 MHz carrier frequency
1
0
1
X
13.56 MHz carrier frequency,
180
° phase-shift relative to TX1
11
0
LOW
1
0
1
13.56 MHz carrier frequency
1
0
1
0
HIGH
1
0
1
13.56 MHz carrier frequency,
180
° phase-shift relative to TX1
1
0
X
13.56 MHz carrier frequency
1
X
13.56 MHz carrier frequency,
180
° phase-shift relative to TX1