User Manual

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© Jennic 2008 JN-DS-JN5139 v1.5 71
Appendix B Development Support
B.1 Crystal Oscillator
16MHz Crystal Requirements
Parameter Min Typ Max Notes
Crystal Frequency 16MHz
Crystal Tolerance 40ppm Including temperature
and ageing
Crystal ESR (Rm)
1
20 Ω 60 Ω
See below for more
details
Crystal Load Capacitance (CL) 9pF See below for more
details
External Capacitors (C1 & C2) 15pF
Total external
capacitance needs to be
2*CL. , allowing for stray
capacitance from chip,
package and PCB
B.1.1 Crystal Equivalent Circuit
Cs
Lm
Cm
Rm
C2C1
Where m C is the motional capacitance
m L is the motional inductance. This together with m C defines the oscillation frequency (series)
m R is the equivalent series resistance ( ESR ).
S C is the shunt or package capacitance and this is a parasitic