SWRS111G June   2011  – January 2026 CC1121

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Functional Diagram
  6. 5 Terminal Configuration and Functions
    1. 5.1 Pin Diagram
    2. 5.2 Pin Configuration
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings #GUID-8A1DE4F5-4E49-477E-A98C-459BEC46A38F/LIT19484635 #GUID-8A1DE4F5-4E49-477E-A98C-459BEC46A38F/LIT89009562
    2. 6.2  Handling Ratings
    3. 6.3  Recommended Operating Conditions (General Characteristics)
    4. 6.4  Thermal Resistance Characteristics for RHB Package
    5. 6.5  RF Characteristics
    6. 6.6  Regulatory Standards
    7. 6.7  Current Consumption, Static Modes
    8. 6.8  Current Consumption, Transmit Modes
      1. 6.8.1 950-MHz Band (High-Performance Mode)
      2. 6.8.2 868-, 915-, and 920-MHz Bands (High-Performance Mode)
      3. 6.8.3 434-MHz Band (High-Performance Mode)
      4. 6.8.4 169-MHz Band (High-Performance Mode)
      5. 6.8.5 Low-Power Mode
    9. 6.9  Current Consumption, Receive Modes
      1. 6.9.1 High-Performance Mode
      2. 6.9.2 Low-Power Mode
    10. 6.10 Receive Parameters
      1. 6.10.1 General Receive Parameters (High-Performance Mode)
      2. 6.10.2 RX Performance in 950-MHz Band (High-Performance Mode)
      3. 6.10.3 RX Performance in 868-, 915-, and 920-MHz Bands (High-Performance Mode)
      4. 6.10.4 RX Performance in 434-MHz Band (High-Performance Mode)
      5. 6.10.5 RX Performance in 169-MHz Band (High-Performance Mode)
      6. 6.10.6 RX Performance in Low-Power Mode
    11. 6.11 Transmit Parameters
    12. 6.12 PLL Parameters
      1. 6.12.1 High-Performance Mode
      2. 6.12.2 Low-Power Mode
    13. 6.13 Timing Requirements
    14. 6.14 32-MHz Crystal Oscillator
    15. 6.15 32-MHz Clock Input (TCXO)
    16. 6.16 32-kHz Clock Input
    17. 6.17 32-kHz RC Oscillator
    18. 6.18 I/O and Reset
    19. 6.19 Temperature Sensor
    20. 6.20 44
    21. 6.21 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1  Block Diagram
    2. 7.2  Frequency Synthesizer
    3. 7.3  Receiver
    4. 7.4  Transmitter
    5. 7.5  Radio Control and User Interface
    6. 7.6  Enhanced Wake-On-Radio (eWOR)
    7. 7.7  Sniff Mode
    8. 7.8  Antenna Diversity
    9. 7.9  Low-Power and High-Performance Mode
    10. 7.10 WaveMatch
  9. 8 Typical Application Circuit
  10. 9 Device and Documentation Support
    1. 9.1 Device and Development-Support Tool Nomenclature
    2. 9.2 Development Support
      1. 9.2.1 Configuration Software
    3. 9.3 Documentation Support
    4. 9.4 Receiving Notification of Documentation Updates
    5. 9.5 Support Resources
    6. 9.6 Trademarks
    7. 9.7 Electrostatic Discharge Caution
    8. 9.8 Glossary
    9. 9.9 Third-Party Products Disclaimer
  11. 10Revision History
  12. 11Mechanical Packaging and Orderable Information

7.8 Antenna Diversity

Antenna diversity can increase performance in a multipath environment. An external antenna switch is required. The CC1121 device uses one of the GPIO pins to automatically control the switch. The device also supports differential output control signals typically used in RF switches.

If antenna diversity is enabled, the GPIO alternates between high and low states until a valid RF input signal is detected. An optional acknowledge packet can be transmitted without changing the state of the GPIO.

An incoming RF signal can be validated by received signal strength or by using the automatic preamble detector. Using the automatic preamble detector ensures a more robust system and avoids the need to set a defined signal strength threshold (such a threshold sets the sensitivity limit of the system).