SWRA495K December   2015  – April 2024 CC1310 , CC1350 , CC2620 , CC2630 , CC2640 , CC2640R2F , CC2640R2F-Q1 , CC2642R-Q1 , CC2650 , CC2662R-Q1

 

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

3 Selecting Crystals for the CC devices

This section presents some important considerations when selecting crystals for the CC devices. Selecting a crystal for a specific application depends on the following three factors:

  • Size (footprint area and height)
  • Performance (accuracy over temperature, lifetime, power consumption, and start-up time)
  • Cost

Consider the following when selecting a crystal:

  • Crystals must be selected to meet requirements listed in the CC data sheets or specifications.
    • ESR must not be greater than can be driven by the CC device.
    • Capacitive loading and frequency tolerance must meet the specifications of the standard used (for example, Blue tooth low energy).
    • Motional inductance must also meet specifications. Many crystal manufactures provide only motional inductance data upon customer request.
  • Some other considerations when selecting a crystal include the following:
    • To improve start-up time and reduce power consumption, the crystal must have the following:
      • Low-capacitive loading, at the expense of greater susceptibility to frequency variation caused by the environment
      • Low-motional inductance
      • Low-motional resistance