SWRS337B December   2025  – June 2026 CC3551E

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Functional Block Diagram
  6. 5 Pin Configuration and Functions
    1. 5.1 Pin Diagram
    2. 5.2 Pin Attributes
    3. 5.3 Signal Descriptions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Electrical Characteristics
    5. 6.5  Thermal Resistance Characteristics
    6. 6.6  WLAN Performance: 2.4-GHz Receiver Characteristics
    7. 6.7  WLAN Performance: 2.4-GHz Transmitter Power
    8. 6.8  WLAN Performance: 5-GHz Receiver Characteristics
    9. 6.9  WLAN Performance: 5-GHz Transmitter Power
    10. 6.10 Bluetooth LE Performance: Receiver Characteristics
    11. 6.11 Bluetooth LE Performance - Transmitter Characteristics
    12. 6.12 Current Consumption - 2.4GHz WLAN Static Modes 
    13. 6.13 Current Consumption - 5GHz WLAN Static Modes
    14. 6.14 Current Consumption - 2.4GHz WLAN Use Cases
    15. 6.15 Current Consumption - Bluetooth LE Static Modes 
    16. 6.16 Current Consumption - MCU Modes
    17. 6.17 Timing and Switching Characteristics
      1. 6.17.1 Clock Specifications
        1. 6.17.1.1 Fast Clock Using an External Crystal (XTAL)
          1. 6.17.1.1.1 External Fast Clock XTAL Specifications
        2. 6.17.1.2 Slow Clock Using Internal Oscillator
        3. 6.17.1.3 Slow Clock Using an External Oscialltor
          1. 6.17.1.3.1 External Slow Clock Oscillator Specifications
        4. 6.17.1.4 Slow Clock Using an External Crystal (XTAL)
          1. 6.17.1.4.1 External Slow Clock XTAL Specifications
      2. 6.17.2 Peripheral Characteristics
        1. 6.17.2.1  ADC
          1. 6.17.2.1.1 ADC Electrical Specifications
        2. 6.17.2.2  I2C
          1. 6.17.2.2.1 I2C Timing Parameters
          2. 6.17.2.2.2 I2C Timing Diagram
        3. 6.17.2.3  SPI
          1. 6.17.2.3.1 SPI Timing Parameters - Controller Mode
          2. 6.17.2.3.2 SPI Timing Diagrams - Controller Mode
          3. 6.17.2.3.3 SPI Timing Parameters - Peripheral Mode
          4. 6.17.2.3.4 SPI Timing Diagrams - Peripheral Mode
        4. 6.17.2.4  xSPI
          1. 6.17.2.4.1 QSPI Timing Parameters
        5. 6.17.2.5  UART
          1. 6.17.2.5.1 UART Timing Parameters
        6. 6.17.2.6  I2S
          1. 6.17.2.6.1 I2S Timing Parameters - Controller Mode
          2. 6.17.2.6.2 I2S Timing Parameters - Peripheral Mode
        7. 6.17.2.7  PDM
          1. 6.17.2.7.1 PDM Timing Parameters
        8. 6.17.2.8  CAN
          1. 6.17.2.8.1 CAN Characteristics
        9. 6.17.2.9  SDMMC
          1. 6.17.2.9.1 SDMMC Timing Parameters - Default Speed 
          2. 6.17.2.9.2 SDMMC Timing Parameters - High Speed 
        10. 6.17.2.10 SDIO
          1. 6.17.2.10.1 SDIO Timing Parameters - Default Speed 
          2. 6.17.2.10.2 SDIO Default Timing
          3. 6.17.2.10.3 SDIO Timing Parameters - High Speed 
          4. 6.17.2.10.4 SDIO High Speed Timing
  8. 7 Detailed Description
    1. 7.1  Overview
    2. 7.2  Arm Cortex-M33 Processor
    3. 7.3  Wireless Subsystem
      1. 7.3.1 WLAN
      2. 7.3.2 Bluetooth Low Energy
    4. 7.4  Memory Subsystem (MEMSS)
      1. 7.4.1 External Memory Interface
    5. 7.5  Hardware Security Module
    6. 7.6  Debug Subsystem (DEBUGSS)
    7. 7.7  General Purpose Timers
    8. 7.8  Real Time Clock (RTC)
    9. 7.9  Direct Memory Access (DMA)
    10. 7.10 Serial Peripherals and I/Os
  9. 8 Applications, Implementation, and Layout
  10. 9 Device and Documentation Support
    1. 9.1 Third-Party Products Disclaimer
    2. 9.2 Device Nomenclature
    3. 9.3 Tools and Software
    4. 9.4 Documentation Support
    5. 9.5 Support Resources
    6. 9.6 Trademarks
    7. 9.7 Electrostatic Discharge Caution
    8. 9.8 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

6.17.1.4 Slow Clock Using an External Crystal (XTAL)

For optimal power consumption, the slow clock can be generated externally by an oscillator, XTAL, or sourced from elsewhere in the system. If using an XTAL, the external source must meet the requirements listed below. The crystal pins should be fed into the CC355xE pins LFXT_P/ GPIO0 and LFXT_N/GPIO1.