JN516X Datasheet, PDF (85/94 Pages) NXP Semiconductors – IEEE802.15.4 Wireless Microcontroller

B.2 32MHz Oscillator
The JN516x contains the necessary on-chip components to build a 32 MHz reference oscillator with the addition of an
external crystal resonator, two tuning capacitors. The schematic of these components are shown in Figure 51. The
two capacitors, C1 and C2, will typically be 15pF ±5% and use a COG dielectric. For a detailed specification of the
crystal required and factors affecting C1 and C2 see Appendix B.1. As with all crystal oscillators the PCB layout is
especially important, both to keep parasitic capacitors to a minimum and to reduce the possibility of PCB noise being
coupled into the oscillator.
JN516x
XTALIN
R1
XTALOUT
C1
C2
Figure 51: Crystal Oscillator Connections
The clock generated by this oscillator provides the reference for most of the JN516X subsystems, including the
transceiver, processor, memory and digital and analogue peripherals.
32MHz Crystal Requirements
Parameter
Crystal Frequency
Min
Typ
Max
32MHz
Notes
Crystal Tolerance
40ppm
Including temperature
and ageing
Crystal ESR Range (Rm)
Crystal Load Capacitance
Range (CL)
10Ω
60Ω
See below for more
details
6pF
9pF
12pF
See below for more
details
Not all Combinations of Crystal Load Capacitance and ESR are Valid
Recommended Crystal
External Capacitors (C1 & C2)
For recommended Crystal
Load Capacitance 9pF and max ESR 40 Ω
15pF
CL = 9pF, total external
capacitance needs to be
2*CL. , allowing for stray
capacitance from chip,
package and PCB
© NXP Laboratories UK 2013
JN-DS-JN516x v1.1 Production
85