nRF904 Nordic VLSI, nRF904 Datasheet - Page 10

• Manufacturer Part Number: nRF904
• Description: RF Transmitter 902-928MHz
• Manufacturer: Nordic VLSI

PRODUCT SPECIFICATION
Suitable 15nH inductors are listed in Table 8.
Modulation is achieved by pulling of the crystal capacitance. As such to achieve
correct frequency deviation operation as specified in Table 4 the crystal must meet the
following specification:
Parallel resonant frequency: fp = transmitter centre frequency divided by 64
Load capacitance:
Series resistance, ESR:
Crystal parallel capacitance: Co < 7 pF
Motional capacitance:
The frequency modulation is achieved by pulling the crystal load by the use of an
internal varactor. As the external resistor R4 is varied, the varactor voltage swing will
vary linearly. R4 is equal to the sum of resistor values if an input filter is used as
shown in Figure 5. Changing the value of R4 enables easy variation of the frequency
deviation, see Figure 9.
Nordic VLSI ASA
Revision: 2.1
Pulse
Coilcraft
muRata
Stetco
KOA

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Figure 9. Typical RF Frequency Deviation for varing values of R4.
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10
Table 8. Vendors and part no. for suitable 15nH inductors.
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http://www.pulseeng.com
http://www.coilcraft.com
http://www.murata.com
http://www.stetco.com
http://www.koaspeer.com
Vestre Rosten 81, N-7075 Tiller, Norway
15
CL = 10 pF
Rs < 60 ohm
Cs = 9 fF (Guideline specification)
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PE-0603CD150GTT
0603CS-15NXGBC
LQW1608A15NG00
0603G150GTE
KQ0603TE15NG
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Phone [phone]
30
35
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Fax [phone]
October 2001