AN3255 Datasheet, PDF (10/24 Pages) STMicroelectronics – Building an RFID short-range reader using the STM8S-DISCOVERY

Application description
AN3255
Table 2. List of PCB passive components (continued)
Component description
Value
Comment
R8
C1, C2
0Ω
Capacitor
7 pF
Serial resistor allowing to fine
tune the quality factor of the
reader antenna
crystal oscillator capacitors
C3
C4
C5
C6
C7, C7’
C8, C8’
D1 (N4148)
22 nF
22 μF
5 pF (50 V)
100 nF
220 pF (50 V), 56 pF (50 V)
82 pF (50 V), 22 pF (50 V)
Diode
-
-
-
-
Capacitors allowing to fine tune
the RLC resonant frequency
impedance adaptation of the
RLC resonant circuit.
Optional
L3,L4,L5,L6, L7 multilayer SMD
ferrites
Ferrite
Removal of parasites for tag
data reception and I²C
Table 3. List of PCB packaged components
Part name
Component name
Description
CR14/CRX14
13.56 MHz crystal
Short-range RFID
couplers
Crystal
Contactless coupler
compliant with short-
range ISO14443 type-B
standard
Generates a 13.56 MHz
carrier frequency
Package
SO16
XTALCMS
Table 4. List of tag packaged components
Part name
Component name
Description
SRI2K
13,56 MHZ short-range Short-range contactless
contactless memory memory used to build a
chip
tag
Package
SBN18
Table 5. List of other passive components
Component description
Value
Resistor
R_P1, R_P2 resistors
4,7 KΩ
Comment
Pull-up for I²C open-drain
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Doc ID 17784 Rev 1