NRF2401AG Nordic VLSI, NRF2401AG Datasheet - Page 34

• Manufacturer Part Number: NRF2401AG
• Manufacturer: Nordic VLSI

PRODUCT SPECIFICATION
nRF2401A Single Chip 2.4 GHz Radio Transceiver
frequency. When clocking the nRF2401A externally, XC2 is not used and can be left
as an open pin.
Frequency Reference MCU
In direct mode there is a requirement on the accuracy of the data rate. For the receiver
to detect the incoming data and recover the clock, the data rate must be within
±200ppm, given that the data is "random", i.e. there is a statistical calculation on how
often a preamble like sequence is present in the data. The clock is synchronized for
any preamble detection, be it a dedicated preamble or part of the data stream.
PCB layout and de-coupling guidelines
A well-designed PCB is necessary to achieve good RF performance. Keep in mind
that a poor layout may lead to loss of performance, or even functionality, if due care is
not taken. A fully qualified RF-layout for the nRF2401A and its surrounding
components, including matching networks, can be downloaded from
www.nordicsemi.no .
A PCB with a minimum of two layers including a ground plane is recommended for
optimum performance. The nRF2401A DC supply voltage should be de-coupled as
close as possible to the VDD pins with high performance RF capacitors, see Table 22.
It is preferable to mount a large surface mount capacitor (e.g. 4.7µF tantalum) in
parallel with the smaller value capacitors. The nRF2401A supply voltage should be
filtered and routed separately from the supply voltages of any digital circuitry.
Long power supply lines on the PCB should be avoided. All device grounds, VDD
connections and VDD bypass capacitors must be connected as close as possible to the
nRF2401A IC. For a PCB with a topside RF ground plane, the VSS pins should be
connected directly to the ground plane. For a PCB with a bottom ground plane, the
best technique is to have via holes as close as possible to the VSS pads. One via hole
should be used for each VSS pin.
Full swing digital data or control signals should not be routed close to the crystal or
the power supply lines.
Nordic Semiconductor ASA
- Vestre Rosten 81, N-7075 Tiller, Norway
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Phone [phone]
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Fax [phone]
Page 34 of 40
Revision: 1.1
March 2006