si4430 Silicon Laboratories, si4430 Datasheet - Page 74

• Manufacturer Part Number: si4430
• Description: Si4430 Ism Transceiver
• Manufacturer: Silicon Laboratories

Si4430
11. Application Notes
This section offers a brief introduction to a number of application related topics. Further recommended reading can
be found in our related application notes at http://www.silabs.com.
11.1. Crystal Selection
The recommended crystal parameters are given in Table 26.
The internal XTAL oscillator will work over a range for the parameters of ESR, CL, C0, and ppm accuracy. Extreme
values may affect the XTAL start-up and sensitivity of the link. For questions regarding the use of a crystal
parameters greatly deviating from the recommend values listed above, please contact customer support.
The crystal used for engineering evaluation and the reference design is the SIWARD –SX2520– 30.0 MHz –
12.0R. Ordering number XTL581200JIG.
11.2. Layout Practice
The following are some general best practice guidelines for PCB layout using the EZRadioPro devices:
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Bypass capacitors should be placed as close as possible to the pin.
TX/RX matching/layout should mimic reference as much as possible. Failing to do so may cause loss
inperformance.
A solid ground plane is required on the backside of the board under TX/RX matching components
Crystal should be placed as close as possible to the XIN/XOUT pins and should not have VDD traces running
underneath or near it.
The paddle on the backside of the QFN package needs solid grounding and good soldered connection
Use GND stitch vias liberally throughout the board, especially underneath the paddle.
Frequency
30 MHz
60 Ω
ESR
Table 26. Recommended Crystal Parameters
12 pF
Preliminary Rev. 0.4
C
L
5 pF
C
0
Frequency Accuracy
±20 ppm