NRF2402 Datasheet, PDF (26/31 Pages) List of Unclassifed Manufacturers – Single chip 2.4 GHz Transmitter

PRODUCT SPECIFICATION
nRF2402/nRF2402G Single Chip 2.4 GHz Radio Transmitter
larger than 0.4 V-peak. The needed input swing is independent of the crystal frequency.
When using external crystal refernce, 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 nRF2402/nRF2402G 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 nRF2402/nRF2402G DC supply voltage should be de-coupled as close as
possible to the VDD pins with high performance RF capacitors, see Table 18. It is preferable
to mount a large surface mount capacitor (e.g. 4.7µF tantalum) in parallel with the smaller
value capacitors. The nRF2402/nRF2402G 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
nRF2402/nRF2402G IC. The VSS pins should be connected directly to the ground plane.
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 - Phone [phone] - Fax [phone]
Revision: 2.0
Page 26 of 31
April 2005