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CC2640R2F: Query for part CC2640R2FRHB

Rupal Sharma
Prodigy 30 points

Part Number: CC2640R2F
Other Parts Discussed in Thread: CC2650

Hi,

 


We would like to have your support on understanding below points regarding CC2640R2FRHB, which is a BLE MCU used in our products:
  1. To better understand the working, we would like to know how the differential signals look like from RF_P and RF_N.
  2. We would like to measure Return loss of complete RF path (starting from the RF_P and RF_N pins to the antenna) using VNA. Is there any practical way to check it.
Please find the attached details on how our part of our circuit looks and the PCB layout.
Kindly let us know for any resources and method to achieve the above objectives.Query.pdf 
  • 0
    TI__Mastermind 36550 points

    Hi,

    If you want to measure the complete RF path then recommend the following:

    1. Remove the CC2650 from the PCB
    2. Assemble semi-rigid cable #1 shield to QFN GND pad and de-embedd the RF cable
    3. Solder feed point of semi-rigid cable #1 to RF_P
    4. Assemble semi-rigid cable #2 shield to QFN GND pad and de-embedd the RF cable
    5. Solder feed point of semi-rigid cable #2 to RF_N
    6. Connect semi-rigid cable #1 and semi-rigid cable #2 to VNA. Configure these ports as differential and then measure S11

    Removing the antenna and connecting a semi-rigid cable #3 at L13 pad 2, will allow you to measure the filter characteristics with S21. 

    You should be using a 4-ports VNA that can measure up to the 3rd harmonic. i.e. a frequency range of 2 GHz to 7.5 GHz.

    Hope this helps.