SLUUDH6 April   2026 CC3501E , CC3551E

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Overview
  5. 2Schematic Considerations - CC35xxE IC
    1. 2.1 Schematic Reference Design
    2. 2.2 Power Supply
      1. 2.2.1 Power Input/Output Requirements
        1. 2.2.1.1 LDO Recommendations
      2. 2.2.2 Boot Sequence
        1. 2.2.2.1 Hosted Mode (Power up by reset pin)
        2. 2.2.2.2 Standalone Mode (Power up when supply above threshold)
        3. 2.2.2.3 SOP Modes
    3. 2.3 Clock Source
      1. 2.3.1 Fast Clock
      2. 2.3.2 Slow Clock
        1. 2.3.2.1 Slow Clock Generated Internally
        2. 2.3.2.2 Slow Clock Using an External Oscillator
        3. 2.3.2.3 Slow Clock Using an External Crystal (XTAL)
    4. 2.4 Radio Frequency (RF)
    5. 2.5 Digital Interfaces
      1. 2.5.1 xSPI
        1. 2.5.1.1 External Serial Flash
      2. 2.5.2 Serial Wire Debug (SWD)
      3. 2.5.3 Logger
      4. 2.5.4 Coexistence
    6. 2.6 Stacked PSRAM Variant
  6. 3Layout Considerations - CC35xxE IC
    1. 3.1 Layout Reference Design
      1. 3.1.1 Reference Design - CC355xE Dual Band Layout
    2. 3.2 IC Thermal Pad
    3. 3.3 Radio Frequency (RF)
    4. 3.4 XTAL
    5. 3.5 Power Supplies
    6. 3.6 External Flash Layout

3.4 XTAL

Figure 3-7 shows the placement and layout around the 52 MHz XTAL and its connections to the CC35xxE IC.

Figure 3-7 is sampled from the LP-EM-CC35X1 design files.

52MHz XTAL From LP-EM-CC35X1 Figure 3-7 52MHz XTAL From LP-EM-CC35X1

When integrating the XTAL, please follow these guidelines:

  • The traces connecting the XTAL to the CC35xxE (XTAL_P and XTAL_M) be as short as possible with matching trace length.
  • Place a 150 Ω resistor on the XTAL_P pin (pin 6) as close as possible to the CC35xxE.
  • The two loading capacitors should be parallel to the edge of the XTAL.
  • Wherever possible, there should be increased ground via stitching around the XTAL for optimal isolation.