The following provides a basic explanation of design considerations for the external oscillation circuit using quartz crystal for 'Low Power RF' technology including ZigBee,IEEE802.15.4 wireless applications. "Please refer to NXP Semiconductors ZigBee/IEEE802.15.4 solution below."
Please refer to NXP Semiconductors official site for additional information.
In realizing low power consumption RF designs, the following factors should be taken into consideration.
1. Oscillation start-up time
2. Frequency tuning
3. Lower BER(Bit Error Rate) over operating temperature
No.
Oscillation Circuit Factor
2.4 GHz
< AT crystal unit spec.>
1
Quick oscillation start-up time
*High oscillation allowance
*Boost inverter
*Lower ESR(R1)
*High drive level
2
Easy frequency control
*inner frequency tuning capacitor
*proper frequency sensitivity
*low parameters' variation
3
Lower BER
*temperature compensation
*High frequency stability
MHz Crystal equivalent circuit
Rapid Oscillation start-up time
--> Lower ESR (R1) , Higher C1
--> Higher drive level
Suitable Frequency Tuning
--> Lower parameters variation(C0,C1,L1,ESR)
Suitable Frequency Tuning
--> Proper Sensitivity (CL,C0)
Higher Frequency Stability
--> Stable fSTA
QMEMS Technology
Worldwide
MC1320x (RF)
MC1321x (SiP)
MC1322x (SoC)
MC1323x (SoC)
US
Europe
Japan
Asia
ZigBee
IEEE802.15.4
2400 to 2483.5 MHz
Recommendable
Clock Devices
S3225
16 MHz 9 pF
(S3225-16.000M-9-10-18-E)
S3225
24 MHz 9 pF
(S3225-24.000M-9-10-15-E)
S3225
32 MHz
Notes:Above recommendations are based on actual evaluation results and intended to support users in picking the right components. And the results are only according to the sample set that received from our customers, so it is not including the dispersion trend of IC and the external parts.
As the actual board layout and choice of external components influences the best suitable crystal load capacitance, We do not assume any responsibility and grant warranty for above recommendations. Users design must be verified and decided by own and individual evaluation.
*ZigBee is a registered trademark of Koninklijke Philips Electronics N.V.
