JN5139/001,515 NXP Semiconductors, JN5139/001,515 Datasheet - Page 77

• Manufacturer Part Number: JN5139/001,515
• Description: IC MCU 32BIT 56QFN
• Manufacturer: NXP Semiconductors

Specifications of JN5139/001,515

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

B.2 16MHz Oscillator
The JN5139 contains the necessary on-chip components to build a 16 MHz reference oscillator with the addition of
an external crystal resonator, two tuning capacitors and a resistor. The schematic of these components are shown in
Figure 49. The two capacitors, C1 and C2, will typically be 15pF ±5% and use a COG dielectric, R2 should be 1M5Ω.
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.
The clock generated by this oscillator provides the reference for most of the JN5139 subsystems, including the
transceiver, processor, memory and digital and analogue peripherals.
© NXP Laboratories UK 2010
R2
Crystal Oscillator Transconductance Versus Supply Voltage
XTALIN
1.32
1.28
1.26
1.24
1.22
1.3
1.2
2.2
Figure 49: Crystal oscillator connections
2.4
C1
JN-DS-JN5139 1v9
2.6
(Temp=25C)
R1
Supply Voltage (VDD)
2.8
3.0
C2
XTALOUT
JN5139
3.2
3.4
3.6
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