Texas Instruments Chipcon CC2420DK, User Manual, Page: 4 / 32

SWRU045 Page 4 of 32
CC2420 Evaluation Module
The CC2420EM Evaluation Module contains the CC2420 chip together with the external
circuitry needed for proper operation. Not all components are needed in an actual application.
Please see the data sheet for a typical application circuit.
The CC2420 operates in the 2.4 GHz frequency band. Although this frequency band is
usually described as “world-wide”, some countries do not allow unlicensed operation in this
band.
Important: Contact your local telecommunication authorities before transmitting an RF signal.
Circuit description
The CC2420 RF section includes all the necessary components for correct operation.
The CC2420 is connected to a 16 MHz crystal.
The user can select between using the CC2420 on chip voltage regulator, or the regulator on
the CC2400EB. This is controlled by the jumper on CC2420EM. The default setting is to use
the CC2400EB regulator. If the internal regulator is selected, you must also change the
CC2400EB P12 jumper setting as given in figure 9.
The CC2420EM Evaluation Module can be plugged into the CC2400B Evaluation Board. Two
2x10 pin pin row connectors with 0.050-inch pitch are used for this purpose.
Figure 1: CC2420EM Evaluation Module
PCB layout, CC2420EM
RF circuits operating at high frequencies are sensitive to the physical layout of the PCB.
Chipcon has carefully optimized the layout of the CC2420EM Evaluation Module and we
therefore recommend that the user copies it when making own PCB designs.
The PCB is of a 4-layer type in order to provide a well-defined ground plane as well as
adequate routing space. The laminate used is standard FR-4 board material. The PCB is
1.0mm thick, with layer 1 on the top side, layers 2 and 3 are internal layers and layer 4 is on
the bottom side. Layers 1 and 4 are used for routing, and layer 3 is used for power routing. All
areas not utilized for routing are filled with copper connected to ground to provide RF
shielding. The ground planes on all layers are stitched together with closely spaced vias.