SWRA495L
December 2015 – April 2025
1
Abstract
Trademarks
1
Oscillator and Crystal Basics
1.1
Oscillator Operation
1.2
Quartz Crystal Electrical Model
1.2.1
Frequency of Oscillation
1.2.2
Equivalent Series Resistance
1.2.3
Drive Level
1.2.4
Crystal Pulling
1.3
Negative Resistance
1.4
Time Constant of the Oscillator
2
Overview of Crystal Oscillators for CC devices
2.1
24MHz and 48MHz Crystal Oscillator
2.2
24MHz and 48MHz Crystal Control Loop
2.3
32.768kHz Crystal Oscillator
3
Selecting Crystals for the CC devices
3.1
Mode of Operation
3.2
Frequency Accuracy
3.2.1
24MHz and 48MHz Crystal
3.2.2
32.768kHz Crystal
3.3
Load Capacitance
3.4
ESR and Start-Up Time
3.5
Drive Level and Power Consumption
3.6
Crystal Package Size
4
PCB Layout of the Crystal
5
Measuring the Amplitude of the Oscillations of Your Crystal
5.1
Measuring Start-Up Time to Determine HPMRAMP1_TH and XOSC_HF_FAST_START
6
Crystals for CC13xx, CC26xx, CC23xx and CC27xx
7
High Performance BAW Oscillator
8
CC23XX and CC27XX Software Amplitude Compensation
9
Internal Capacitor Array for CC23XX and CC27XX
10
Internal Capacitor Array for CC13xx and CC26xx
11
Summary
12
References
13
Revision History
Application Note
Crystal Oscillator and Crystal Selection for the CC13xx, CC26xx, CC23xx, and CC27xx Family of Wireless MCUs