Silicon Laboratories SI4421 - Manual (Page 41)

Si4421
Evaluation Board with Resonant PCB Antenna (BIFA)
Schematics
*
*
* See values in the table
L1
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
37 38
39 40
CS1
C6
C3 C2
Q1
A
R
SSI
C4
TP1
C1
FFS
/D
A
T
A
SEL SC
K
SD
I
SD
O
IR
Q
FFE VD
I
1
2
3
JP1
TP3
SDI
1
SCK 2
NSEL 3
SDO
4
NIRQ
5
FSK/DATA/NFFS
6
DCLK/CFIL
7
NINT/VDI
16
XTL/REF
9
CLK
8
VSS
11
RF2
12
RF1 13
VDD 14
ARSSI
15
NRES
10
IC1
CL
K
_O
UT
R6
R7
R5 R8
ARSSI
RESET
RESET
SDI
SDI
SCK
SCK
SEL
SEL
SDO
SDO
IRQ
IRQ
DATA
DATA
DATA
DATA DCLK
DCLK
DCLK
DTO
DTO
CLKIN
CLKIN
VDI
VDI
VDI
CON40-0 100pF
10nF
GND
GND
GND
GND
10M
H
z
VD
D VD
D
10nF
GND
2.2uF
GN
D
IA4421
10k
100k
10k
10k
Note: Components R5 to R8 and C6 are needed for connection to the ISM Chipset Development Kit load board (IA ISM-DK3) and are
not necessary in an application.
Frequency Dependent Component Values
Band C3 [pF] L1 [nH]
868 MHz 47 22
Dual (868/915 MHz) 47/33 18
915 MHz 33 15
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