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Si4421
REFERENCE DESIGNS
Evaluation Board with 50 Ohm Matching Network
Schematics
CLK_OUT
ARSSI
C8
C10
C9 C11
L1L4
L2
L3
AN
T
**
*
*
*
*
*
*
* See values in the table
*
optional
C3 C2
C4
C1
SDI
1
SCK
2
NSEL
3
SDO
4
NIRQ
5
FSK/DATA/NFFS
6
DCLK/CFIL/FFIT
7
NINT/VDI
16
XTL/REF
9
CLK
8
VSS
11
RF2
12
RF1
13
VDD
14
ARSSI
15
NRES
10
IC1
TP61
CN62
1
2
3
4
5
6
7
8
9
10
11
12
13
14
CN61
TP62
Q61
MATCHING_NETWORK
VDD
GND
GND
ARSSI
ARSSI
RESET
RESET
SDI
SDI
SCK
SCK
SEL
SEL
SDO
SDO
IRQ
IRQ
DATA
DATA
DCLK
DCLK
VDI
VDI
10nF
GND
GND
GND
VDD
VDD
4.7nF
GND
2.2uF
GND
IA4421
VDD
GND
GND
VDD
10MHz
GND
Frequency Dependent Component Values
f [MHz] L1 [nH] L2 [nH] L3 [nH] L4 [nH] C8 [pF] C9 [pF] C10 [pF] C11 [pF] C3 [pF]
434 18 47 390 18 5 2.7 2.7 220 220
868 3.9 18 100 3.9 2.7 1.2 1.8 47 47
915 3.6 16 100 3.6 2.7 1.2 1.8 33 33
Recommended Component Types
Part number
Component Manufacturer
434MHz 868 MHz 915MHz
Note
L1 Coilcraft 0603CS-18NX 0603CS-3N9X 0603CS-3N9X 1
L4 Coilcraft 0603CS-18NX 0603CS-3N9X 0603CS-3N9X 1
L2 Coilcraft 0603CS-47NX 0603CS-18NX 0603CS-16NX 1
L3 Coilcraft 0603CS-R39X 0603CS-R10X 0603CS-R10X 2
C9 Murata GRM1885C1H2R7CZ01B GRM1885C1H1R2CZ01B GRM1885C1H1R2CZ01B 3
C8 Murata GRM1885C1H5R0CZ01B GRM1885C1H2R7CZ01B GRM1885C1H2R7CZ01B 3
C10 Murata GRM1885C1H2R7CZ01B GRM1885C1H1R8CZ01B GRM1885C1H1R8CZ01B 3, 4
C11 Murata GRM1885C1H221JA01B GRM1885C1H470JZ01B GRM1885C1H330JZ01B 3
C3 Murata GRM1885C1H221JA01B GRM1885C1H470JZ01B GRM1885C1H330JZ01B 3
For component selection guidelines, see the notes on the next page.
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