CC2500RGPR Datasheet, PDF (12/99 Pages) Texas Instruments – Low-Cost Low-Power 2.4 GHz RF Transceiver

CC2500
4.4
Crystal Oscillator
Tc = 25C, VDD = 3.0 V if nothing else stated.
Parameter
Crystal frequency
Tolerance
ESR
Start-up time
Min Typ Max Unit Condition/Note
26 26 27 MHz
±40
ppm This is the total tolerance including a) initial tolerance, b) crystal
loading, c) aging, and d) temperature dependence.
The acceptable crystal tolerance depends on RF frequency and
channel spacing / bandwidth.
100 
150
µs Measured on CC2500EM reference design ([4]) using crystal
AT-41CD2 from NDK.
This parameter is to a large degree crystal dependent.
Table 7: Crystal Oscillator Parameters
4.5
Low Power RC Oscillator
Tc = 25C, VDD = 3.0 V if nothing else stated. All measurement results obtained using the CC2500EM reference design
([4]).
Parameter
Calibrated frequency
Frequency accuracy after
calibration
Temperature coefficient
Supply voltage coefficient
Initial calibration time
Min
Typ
Max
Unit Condition/Note
34.7 34.7
36
kHz Calibrated RC oscillator frequency is XTAL
frequency divided by 750
-1 /
%
The RC oscillator contains an error in the
+10
calibration routine that statistically occurs in
17.3% of all calibrations performed. The given
maximum accuracy figures account for the
calibration error. Refer also to the CC2500
Errata Notes.
+0.4
% / C Frequency drift when temperature changes
after calibration
+3
% / V Frequency drift when supply voltage changes
after calibration
2
ms
When the RC oscillator is enabled, calibration
is continuously done in the background as long
as the crystal oscillator is running.
Table 8: RC Oscillator Parameters
SWRS040C
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