CC2500 Datasheet, PDF (11/76 Pages) Texas Instruments – Single Chip Low Cost Low Power RF Transceiver

CC2500
4.5 Low Power RC Oscillator
Typical performance is for Tc = 25°C @ VDD = 3.0 V if nothing else is stated. The values in the table are simulated results
and will be updated in later versions of the data sheet.
Parameter
Calibrated frequency
Frequency accuracy after
calibration
Temperature coefficient
Supply voltage coefficient
Initial calibration time
Wake-up period
Min
Typ
Max Unit
Condition/Note
34.6 34.7
36
kHz Calibrated RC Oscillator frequency is XTAL
frequency divided by 750
+0.3
%
-10
+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.
58e-6
59650 Seconds Programmable, dependent on XTAL frequency
Table 8: RC Oscillator Parameters
4.6 Frequency Synthesizer Characteristics
Tc = 25°C, VDD = 3.0 V if nothing else stated. All measurements were performed using the CC2500EM reference design.
Parameter
Min Typ
Max Unit
Condition/Note
Programmed
frequency resolution
397 F_XOSC/
412
2¹⁶
Hz 26-27 MHz crystal.
Synthesizer frequency
±40
tolerance
ppm Given by crystal used. Required accuracy (including
temperature and aging) depends on frequency band and
channel bandwidth / spacing.
RF carrier phase noise
–78
dBc/Hz @ 50 kHz offset from carrier
RF carrier phase noise
–78
dBc/Hz @ 100 kHz offset from carrier
RF carrier phase noise
–81
dBc/Hz @ 200 kHz offset from carrier
RF carrier phase noise
–90
dBc/Hz @ 500 kHz offset from carrier
RF carrier phase noise
–100
dBc/Hz @ 1 MHz offset from carrier
RF carrier phase noise
–108
dBc/Hz @ 2 MHz offset from carrier
RF carrier phase noise
–116
dBc/Hz @ 5 MHz offset from carrier
RF carrier phase noise
–127
dBc/Hz @ 10 MHz offset from carrier
PLL turn-on / hop time
90
µs Time from leaving the IDLE state until arriving in the RX,
FSTXON or TX state, when not performing calibration.
Crystal oscillator running.
PLL RX/TX and
10
TX/RX settling time
µs Settling time for the 1xIF frequency step from RX to TX,
and vice versa.
PLL calibration time
18739
XOSC Calibration can be initiated manually, or automatically
cycles before entering or after leaving RX/TX.
0.69 0.72 0.72
ms Min/typ/max time is for 27/26/26 MHz crystal frequency.
Table 9: Frequency Synthesizer Parameters
Preliminary Data Sheet (rev.1.1.) SWRS040
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