CC2510_15 Datasheet, PDF (206/245 Pages) Texas Instruments – Low-Power SoC (System-on-Chip) with MCU, Memory,2.4 GHz RF Transceiver, and USB Controller

CC2511F8 - Not Recommended for New Designs
799 μs²⁴. When f_Ref is 24 MHz, these numbers
are 796 μs²⁴ and 865 μs²⁴ respectively.
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 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 75 µs²⁴ when f_Ref is 26 MHz and
81 µs²⁴ when f_Ref is 24 MHz. The blanking
interval between each frequency hop is then
approximately equal to the PLL turn on time.
The VCO current calibration result is available
in FSCAL2 and is not dependent on the RF
frequency. Neither is the charge pump current
calibration result available in FSCAL3. The
same value can therefore be used for all
frequencies.
3) Run calibration on a single frequency at
startup. Next write 0 to FSCAL3[5:4] to
disable the charge pump calibration. After
writing to FSCAL3[5:4] strobe SRX (or STX)
with MCSM0.FS_AUTOCAL=01 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 735 µs²⁴ to 168 µs²⁵
when f_Ref is 26 MHz and from 799 µs²⁴ to 182
µs²⁵ when f_Ref is 24 MHz. The blanking interval
between each frequency hop is then 243 µs
and 263 µs respectively.
There is a trade off between blanking time and
memory space needed for storing calibration
data in non-volatile memory. Solution 2) above
gives the shortest blanking interval, but
requires more memory space to store
calibration values. Solution 3) gives 631 µs
smaller blanking interval than solution 1 when
f_Ref is 26 MHz and 683 µs smaller blanking
interval than solution 1 when f_Ref is 24 MHz).
13.17.3 Wideband Modulation not Using
Spread Spectrum
Digital modulation systems under FCC part
15.247 includes 2-FSK and GFSK modulation.
A maximum peak output power of 1 W (30
dBm) is allowed if the 6 dB bandwidth of the
modulated signal exceeds 500 kHz. In
25 _{TEST0=0x0B. Please see DN110 [11] for}
more details.
CC2510Fx / CC2511Fx
addition, the peak power spectral density
conducted to the antenna shall not be greater
than 8 dBm in any 3 kHz band.
Operating at high data rates and high
frequency separation, the CC2510Fx/CC2511Fx is
suited for systems targeting compliance with
digital modulation systems as defined by FCC
part 15.247. An external power amplifier is
needed to increase the output above 1 dBm.
13.17.4 Data Burst Transmissions
The high maximum data rate of
CC2510Fx/CC2511Fx opens up for burst
transmissions. A low average data rate link
(e.g. 10 kBaud), can be realized using a higher
over-the-air data rate. Buffering the data and
transmitting in bursts at high data rate (e.g.
500 kBaud) will reduce the time in active
mode, and hence also reduce the average
current consumption significantly. Reducing
the time in active mode will reduce the
likelihood of collisions with other systems, e.g.
WLAN.
13.17.5 Crystal Drift Compensation
The CC2510Fx/CC2511Fx has a very fine
frequency resolution (see Table 16). This
feature can be used to compensate for
frequency offset and drift.
The frequency offset between an ‘external’
transmitter and the receiver is measured in the
CC2510Fx/CC2511Fx and can be read back from
the FREQEST status register as described in
Section 13.7.1. The measured frequency offset
can be used to calibrate the frequency using
the ‘external’ transmitter as the reference. That
is, the received signal of the device will match
the receiver’s channel filter better. In the same
way the centre frequency of the transmitted
signal will match the ‘external’ transmitter’s
signal.
13.17.6 Spectrum Efficient Modulation
CC2510Fx/CC2511Fx also has the possibility to
use Gaussian shaped 2-FSK (GFSK). This
spectrum-shaping feature improves adjacent
channel power (ACP) and occupied bandwidth.
In ‘true’ 2-FSK systems with abrupt frequency
shifting, the spectrum is inherently broad. By
making the frequency shift ‘softer’, the
spectrum can be made significantly narrower.
Thus, higher data rates can be transmitted in
the same bandwidth using GFSK.
SWRS055G
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