4021-DKDB14 Silicon Laboratories Inc, 4021-DKDB14 Datasheet - Page 24

• Manufacturer Part Number: 4021-DKDB14
• Description: KIT DEV TEST EZRADIO SI4021 TX
• Manufacturer: Silicon Laboratories Inc

Specifications of 4021-DKDB14

• Accessory Type: Test Card, Transmitter, 434MHz
• Wireless Frequency: 434 MHz
• Interface Type: SPI
• Modulation: FSK, OOK
• 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

CRYSTAL SELECTION GUIDELINES
The crystal oscillator of the Si4021 requires a 10 MHz parallel mode crystal. The circuit contains an integrated load capacitor in order to
minimize the external component count. The internal load capacitance value is programmable from 8.5 pF to 16 pF in 0.5 pF steps. With
appropriate PCB layout, the total load capacitance value can be 10 pF to 20 pF so a variety of crystal types can be used.
When the total load capacitance is not more than 20 pF and a worst case 7 pF shunt capacitance (C
oscillator is able to start up with any crystal having less than 100 ohms ESR (equivalent series loss resistance). However, lower C
values guarantee faster oscillator startup. It is recommended to keep the PCB parasitic capacitances on the XTL pin as low as possible.
The crystal frequency is used as the reference of the PLL, which generates the RF carrier frequency (f
the crystal frequency. The accuracy requirements for production tolerance, temperature drift and aging can thus be determined from the
maximum allowable carrier frequency error.
Maximum XTAL Tolerances Including Temperature and Aging [ppm]
Whenever a low frequency error is essential for the application, it is possible to “pull” the crystal to the accurate frequency by changing the
load capacitor value. The widest pulling range can be achieved if the nominal required load capacitance of the crystal is in the “midrange”,
for example 16 pF. The “pull-ability” of the crystal is defined by its motional capacitance and C
Note:
Bit Rate:
Bit Rate:
Bit Rate:
Bit Rate:

There may be other requirements for the TX carrier accuracy with regards to the requirements as defined by standards and/or
channel separations.
115.2 kbps
38.4 kbps
2.4 kbps
433 MHz
868 MHz
915 MHz
9.6 kbps
433 MHz
868 MHz
915 MHz
433 MHz
868 MHz
915 MHz
433 MHz
868 MHz
915 MHz
don't use
don't use
don't use
don't use
don't use
don't use
30
20
10
10
30
15
30
30
8
8
don't use
don't use
don't use
60
50
25
25
60
50
25
25
60
20
10
10
60
don't use
don't use
don't use
Transmitter Deviation [+/- kHz]
90
75
40
40
Transmitter Deviation [+/- kHz]
90
75
40
40
Transmitter Deviation [+/- kHz]
90
50
30
25
Transmitter Deviation [+/- kHz]
90
don't use
don't use
don't use
120
100
120
100
120
120
60
50
60
50
75
40
40
0
150
100
150
100
150
100
150
75
75
75
70
60
60
30
20
15
.
c
). Therefore f
0
) value is expected for the crystal, the
180
100
180
100
180
100
180
100
75
75
75
75
75
50
30
30
c
is directly proportional to
210
100
100
100
210
100
100
100
210
100
100
210
100
75
50
50
Si4021
0
and ESR
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