4420-DKDB2 Silicon Laboratories Inc, 4420-DKDB2 Datasheet - Page 28

• Manufacturer Part Number: 4420-DKDB2
• Description: KIT DEV TEST EZRADIO SI4420 TRX
• Manufacturer: Silicon Laboratories Inc

Specifications of 4420-DKDB2

• Accessory Type: Test Card, Transceiver, 434MHz
• Wireless Frequency: 434 MHz
• Interface Type: SPI
• Modulation: FSK
• For Use With/related Products: EZRadio®
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

RX-TX ALIGNMENT PROCEDURES
RX-TX frequency offset can be caused only by the differences in the actual reference frequency. To minimize these errors it is suggested to
use the same crystal type and the same PCB layout for the crystal placement on the RX and TX PCBs.
To verify the possible RX-TX offset it is suggested to measure the CLK output of both chips with a high level of accuracy. Do not measure the
output at the XTL pin since the measurement process itself will change the reference frequency. Since the carrier frequencies are derived
from the reference frequency, having identical reference frequencies and nominal frequency settings at the TX and RX side there should be
no offset if the CLK signals have identical frequencies.
It is possible to monitor the actual RX-TX offset using the AFC status report included in the status byte of the receiver. By reading out the
status byte from the receiver the actual measured offset frequency will be reported. In order to get accurate values the AFC has to be
disabled during the read by clearing the "en" bit in the AFC Control Command (bit 0).
TYPICAL APPLICATIONS
Repeater Demo (915 MHz)
Schematics
GND
6V
BATTERY
SEL
CLK
IRQ
SCK
MISO
MOSI
FFS
FFE
INT/VDI
ARSSI
J1
3
2
1
1
2
TX
RX
GND
GND
1
SJ1
TX
RX
2
C3
2,2uF
28
27
26
25
24
23
22
20
19
18
17
16
15
21
2
1
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
C8051F311
IC1
2
3
1
/RST/C2CK
IC3
IA2112-3.3V
IN
GND
ON
P3.0/C2D
OUT
POK
GND
P2.0
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
VDD
P2.1
5
4
14
13
12
11
10
9
8
7
6
5
4
3
GND
C4
2,2uF
GND
3,3V
4
3
6
1
3
2
DEBUG
1
GND
SW1
C1
100nF
R3
820
R5
820
5
GND
VCC
R4
820
R6
820
C5
1uF
R7
1k
C6
100pF
C7
10pF
GND
MOSI
SCK
SEL
MISO
IRQ
FFS
FFE
CLK
2
3
4
5
6
7
8
1
IC2
SDI
SCK
NSEL
SDO
NIRQ
FSK/DATA/NFFS
DCLK/CFIL
CLK
IA4420-REVC
NINT/VDI
XTL/REF
ARSSI
NRES
VDD
VSS
RF2
RF1
16
15
14
13
12
11
10
9
GND
INT/VDI
C2
4,7nF
ARSSI
VCC
GND
Q1
10MHz
Si4420
GND
X1
28