Product data

MFRC631 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.3 — 4 February 2014
227433 105 of 120
NXP Semiconductors
MFRC631
High performance ISO/IEC 14443 A/B reader solution
14. Application information
A typical application diagram using a complementary antenna connection to the
MFRC631 is shown in Figure 33
.
The antenna tuning and RF part matching is described in the application note Ref. 1
and
Ref. 2
.
14.1 Antenna design description
The matching circuit for the antenna consists of an EMC low pass filter (L0 and C0), a
matching circuitry (C1 and C2), and a receiving circuits (R1 = R3, R2 = R4, C3 = C5 and
C4 = C6;), and the antenna itself. The receiving circuit component values needs to be
designed for operation with the MFRC631. A reuse of dedicated antenna designs done for
other products without adaptation of component values will result in degraded
performance.
For a more detailed information about designing and tuning the antenna, please refer to
the relevant application notes:
• MICORE reader IC family; Directly Matched Antenna Design, Ref. 1 and
• MIFARE (14443A) 13.56 MHz RFID Proximity Antennas, Ref. 2.
14.1.1 EMC low pass filter
The MIFARE system operates at a frequency of 13.56 MHz. This frequency is derived
from a quartz oscillator to clock the MFRC631 and is also the basis for driving the antenna
with the 13.56 MHz energy carrier. This will not only cause emitted power at 13.56 MHz
Fig 33. Typical application antenna circuit diagram
001aam269
VDD PVDD
MICRO-
PROCESSOR
host
interface
TVDD
XTAL1 XTAL2
RXN
VMID
TX1
TVSS
TX2
9
82518
19
VSS
33 20
13
14
17
16
15
14
21
28-31
32
PDOWN
IRQ
7
DVDD
AVDD
12
RXP
READER IC
R1
L0
C1
Ra
Ra
C1
L0
R2
R4
C0
C0
C2
C2
C
RXN
C
RXP
C
vmid
R3
27.12 MHz
antenna
Lant