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AFE7955: Maximum peak differential RF input power at device pins for DSA settings 0-3dB

Lester Lopez
Prodigy 25 points
Part Number: AFE7955


Tool/software:

I am looking to use this device in an application where I may be operating at the lower DSA states (0-3dB) and subsequently need to assess the device for non-damage against large input RF power levels.  Can TI please provide the maximum RF input power levels allowed (non-damage condition, not FS inputs) under this low DSA state configuration?  

  • 0
    TI__Mastermind 18221 points

    Hi Lester,

    Rx input pins max DC voltage rating is -0.5V to VDDRX1p8 + 0.3V i.e -0.5 to 2.1V on each side (p and n). Vp-p is 2.6V on each side. So, differentially, it’s twice of this. i.e. 5.2V p-p. On the 100ohm input resitor, this corresponds to 15.3dBm.

    The RF max input in dBm specs are higher than this due to loss in the AFE’s substrate which varies across input frequency range. That’s the reason why P_FS_CW, MAX specification is given for each frequency band separately.

     

    The ADC input can survive below max input signal power for at any programmed DSA value. There’s an RF detector at the input which is used to automatically increases DSA setting (irrespective of programmed DSA value) to protect the input in case the input power exceeds the max supported at that programmed DSA setting. An output pin can be configured to indicate the event trigger of this detector. Note that when input signal exceeds full scale at the programmed DSA, ADC output will be saturated and not usable.

    Regards,

    David Chaparro