SWRA729 April   2022 CC1352P , CC2652P

 

  1.   Trademarks
  2.   Acronyms
  3. 1Reference Designs Available
    1. 1.1 Single Component for 10-dBm PA Port
      1. 1.1.1 Murata PA IPC Equivalent Circuit
      2. 1.1.2 IPC Size and Dimensions
    2. 1.2 CC2652P PA IPC EM
      1. 1.2.1 Component Placement and Layout
      2. 1.2.2 Layout - Layer 1
      3. 1.2.3 Layout - Layer 2
      4. 1.2.4 Layout - Layer 3
      5. 1.2.5 Layout - Layer 4
  4. 2PA IPC Measurement Results
    1. 2.1 CC2652P Output Power, 1-Mbps Bluetooth Low Energy
    2. 2.2 CC2652P TX Efficiency, Harmonics, and Output Power at Various PA Settings
  5. 3Harmonic Emission Regulatory Requirements
    1. 3.1 Compliance with FCC regulations
    2. 3.2 Compliance with Regulations
  6. 4Summary
  7. 5References

3.1 Compliance with FCC regulations

Table 3-2 Examples of FCC Correction Factor and Maximum Duty Cycling
Measured violating harmonic (using maximum output power)-21.23-25-30-35-40-41.23dBm
Regulatory Requirement (2nd or 3rd harmonics)-41.23-41.23-41.23-41.23-41.23-41.23dBm
TX on time (ms)10.0015.4327.4548.8186.80100.00ms
Duty Cycle10.0015.4327.4548.8186.80100.00%
Equation 1. C F = - 20 • log ⁡ t 100   m s

If duty cycling is not an option whilst operating at maximum output power, it is recommended to implement a notch filter or band stop filter to meet the FCC requirements for the 2nd harmonic. The notch filter given in Figure 3-1 consists of one inductor in series with a capacitor. The values of the components as shown in Figure 3-1 is derived by Equation 2, and should sufficiently attenuate the 2nd harmonic. Where L is an inductor and Ctot is the sum of the capacitor C and the parasitic capacitance from the layout. The filter should be connected to the unbalanced port of the PA IPC. However, if a switch is utilized it would be beneficial to place it at the common port of the RF switch so all RF ports will benefit from the additional filtering.

GUID-20220316-SS0I-XTVW-VFCH-PVVNF4T6VMHV-low.pngFigure 3-1 Circuit Diagram of the Notch Filter.
Equation 2. f_c=  1/(2π√(LC_tot ))