CC2510FX Datasheet, PDF (216/253 Pages) List of Unclassifed Manufacturers – True System-on-Chip with Low Power RF Transceiver and 8051 MCU

CC2510Fx / CC2511Fx
15.17 Antenna Interface
The balanced RF input and output of
CC2510Fx/CC2511Fx share two common pins and
are designed for a simple, low-cost matching
and balun network on the printed circuit board.
The receive- and transmit switching at the
CC2510Fx/CC2511Fx front-end is controlled by a
dedicated on-chip function, eliminating the
need for an external RX/TX-switch.
A few passive external components combined
with the internal RX/TX switch/termination
circuitry ensures match in both RX and TX
mode.
Although CC2510Fx/CC2511Fx has a balanced
RF input/output, the chip can be connected to
a single-ended antenna with few external low
cost capacitors and inductors.
The passive matching/filtering network
connected to CC2510Fx/CC2511Fx should have
the following differential impedance as seen
from the RF-port (RF_P and RF_N) towards
the antenna:
Z_out = 80 + j74 Ω
To ensure optimal matching of the
CC2510Fx/CC2511Fx differential output it is
recommended to follow the CC2510EM
reference designs as closely as possible.
Gerber files for the reference designs are
available for download from the Chipcon
website.
15.18 System
considerations
and
Guidelines
15.18.1 SRD Regulations
International regulations and national laws
regulate the use of radio receivers and
transmitters. Short Range Devices (SRDs) for
license free operation are allowed to operate
in the 2.45 GHz bands worldwide. The most
important regulations are EN 300 440 and EN
300 328 (Europe), FCC CFR47 part 15.247
and 15.249 (USA), and ARIB STD-T66
(Japan). A summary of the most important
aspects of these regulations can be found in
Application Note AN032 SRD regulations for
license-free transceiver operation in the 2.4
GHz band, available from the Chipcon
website.
Please note that compliance with regulations
is dependent on complete system
performance. It is the customer’s responsibility
to ensure that the system complies with
regulations.
15.18.2 Frequency Hopping and Multi-Channel
Systems
The 2.400 – 2.4835 GHz band is shared by
many systems both in industrial, office and
home environments. It is therefore
recommended to use frequency hopping
spread spectrum (FHSS) or a multi-channel
protocol because the frequency diversity
makes the system more robust with respect to
interference from other systems operating in
the same frequency band. FHSS also combats
multipath fading.
CC2510Fx/CC2511Fx is highly suited for FHSS or
multi-channel systems due to its agile
frequency synthesizer and effective
communication interface. Using the packet
handling support and data buffering is also
beneficial in such systems as these features
will significantly offload the host controller.
Charge pump current, VCO current and VCO
capacitance array calibration data is required
for each frequency when implementing
frequency hopping for CC2510Fx/CC2511Fx.
There are 3 ways of obtaining the calibration
data from the chip:
1) Frequency hopping with calibration for each
hop. The PLL calibration time is approximately
720 µs.
2) Fast frequency hopping without calibration
for each hop can be done by calibrating each
frequency at startup and saving the resulting
FSCAL3, FSCAL2 and FSCAL1 register values
in MCU memory. Between each frequency
hop, the calibration process can then be
replaced by writing the FSCAL3, FSCAL2 and
FSCAL1 register values corresponding to the
next RF frequency. The PLL turn on time is
approximately 90 µs.
3) Run calibration on a single frequency at
startup. Next write 0hex to FSCAL3[5:4] to
disable the charge pump calibration. After
writing to FSCAL3[5:4] strobe SRX (or STX)
with MCSM0.FS_AUTOCAL = 1 for each new
frequency hop. That is, VCO current and VCO
capacitance calibration is done but not charge
pump current calibration. When charge pump
current calibration is disabled the calibration
time is reduced from approximately 720 µs to
approximately 150 µs.
CC2510Fx/CC2511Fx PRELIMINARY Data Sheet (Rev. 1.2) SWRS055A Page 216 of 252