SWRA834 May   2025 CC2340R5 , CC2340R5-Q1 , CC2744R7-Q1 , CC2745P10-Q1 , CC2745R10-Q1 , CC2745R7-Q1 , CC2755R10

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Reference Designs
    1. 2.1 LP-EM-CC2340R53
    2. 2.2 LP-EM-CC2340R5
    3. 2.3 LP-EM-CC2340R5-Q1
    4. 2.4 LP-EM-CC2340R5-RGE-4x4-IS24
    5. 2.5 LP-EM-CC2745R10-Q1
  6. 3 Schematic
    1. 3.1 Schematic Overview
      1. 3.1.1 48MHz Crystal
      2. 3.1.2 32.768kHz Crystal
      3. 3.1.3 Filter
      4. 3.1.4 Decoupling Capacitors
      5. 3.1.5 Antenna Components
      6. 3.1.6 RF Shield
    2. 3.2 I/O Pins Drive Strength
    3. 3.3 Bootloader Pins
    4. 3.4 Serial Wire Debug (SWD) Pins
  7. 4 PCB Layout
    1. 4.1 Board Stack-Up
    2. 4.2 LC Filter
    3. 4.3 Decoupling Capacitors
    4. 4.4 Placement of Crystal Load Capacitors
    5. 4.5 Current Return Path
    6. 4.6 DC/DC Regulator
    7. 4.7 Antenna Matching Components
    8. 4.8 Transmission Lines
    9. 4.9 Electromagnetic Simulation
  8. 5 Antenna
  9. 6 Crystal Tuning
    1. 6.1 CC23xx and CC27xx Crystal Oscillators
    2. 6.2 Crystal Selection
    3. 6.3 Tuning the LF Crystal Oscillator
    4. 6.4 Tuning the HF Crystal Oscillator
  10. 7 Optimum Load Impedance
  11. 8 PA Table
  12. 9 Power Supply Configuration
    1. 9.1 Introduction to Power Supply
    2. 9.2 DC/DC Converter Mode
    3. 9.3 Global LDO Mode
  13. 10Board Bring-Up
    1. 10.1 Power On
    2. 10.2 RF Test: SmartRF Studio
    3. 10.3 RF Test: Conducted Measurements
      1. 10.3.1 Sensitivity
      2. 10.3.2 Output Power
    4. 10.4 Hardware Troubleshooting
      1. 10.4.1 No Link: RF Settings
      2. 10.4.2 No Link: Frequency Offset
      3. 10.4.3 Poor Link: Antenna
      4. 10.4.4 Bluetooth Low Energy: Device Does Advertising But Cannot Connect
      5. 10.4.5 Poor Sensitivity: Background Noise
      6. 10.4.6 High Sleep Power Consumption
  14. 11Summary
  15. 12References

3.1.4 Decoupling Capacitors

In the reference designs, there are several decoupling capacitors. Take caution when placing the decoupling capacitors, as some pins with the same name are not connected internally. If the decoupling capacitor is placed at the incorrect pin, then the effect of decoupling capacitor gets reduced. The schematic in the reference design for every device shows where each decoupling capacitor needs to be placed at.