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3.2
Functional Description
The TWR-KW2xDxxx is built around Freescale's MKW2XDXXX 56-pin LGA platform and is intended
as a simple evaluation platform and as a building block for application development. The 4-layer board
provides the MKW2XDXXX with its required RF circuitry, 32 MHz reference oscillator crystal and power
supply bypassing. The layout for this base level functionality can be used as a reference layout by the user
target board.
3.2.1
RF Performance and Considerations
TWR-KW2xDxxx transceiver includes a 1mW nominal output power, PA with internal voltage controlled
oscillator (VCO), integrated transmit/receive switch, on-board power supply regulation, and full
spread-spectrum encoding and decoding. Key specifications for MKW2XDXXX are:
•
Nominal output power is 0 dBm, with +10 dBm max
•
Programmable output power from –30 dBm to +10 dBm (measured at the package pin)
•
Frequency range is 2360 to 2480 MHz (Includes both ISM and MBAN bands)
•
Receiver sensitivity: –102 dBm, typical (@1% PER for 20 byte payload packet, measured at the
package pin)
•
Differential bidirectional RF input/output port with integrated transmit/receive switch
The TWR-KW2xDxxx utilizes a minimum number of components while providing good RF performance:
•
Uses a minimum number of RF marching components and external 50:50 balun.
•
"F" printed metal antenna for a small footprint, low cost design.
An external 50 (unbal): 50(bal) balun connects a single-ended 50-ohm port to the differential RF port of
the MKW2XDXXX radio. The layout has provision for out-of-band signal suppression (components L5
and C19) if required.
Freescale Semiconductor
Figure 3-3. TWR-KW2xDxxx RF Circuitry
Tower KW2xDxxx Hardware Reference Manual, Rev. 0.2
TWR-KW2xDxxx
3-5
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