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ONET2804T: Application

Naser S.
Genius 11605 points
Part Number: ONET2804T

My customer used our TI-TIA ONET2804T in their ROSA, when they test RSSI, they got split in different voltage input, please check the plot:

It was tested in Rrssi at 10kohm: (marked red in the second figure), his questions are:

1: why there are splits in the RSSI at different voltage

2. at what value we should set the Rrssi for the best performance, means close to ideal and no split.

Thanks.

  • 0
    TI__Genius 16725 points

    Hello,

    Due to the holidays, we will have delayed responses. I will look into this issue and help resolve it or find an expert who can resolve this for you by the end of next week.

    Thanks!
    -Karan

  • 0 in reply to Karan Kotadia
    TI__Genius 11605 points

    Hi Karan: Hope you had great holidays. Can you  please update on this open forum request. Customer is still waiting. Thanks

  • 0 in reply to Naser S.
    TI__Expert 8070 points
    Hi Naser,

    Can you explain further what the customer means by different input voltages? Are they changing the power supply?

    The ONET2804T RSSI can have a gain variation as high as 8% from nominal with a 3.3V supply. The RSSI could change slightly with power supply due to the biasing of the circuitry changing slightly. However, I would expect that with the same supply and resistor value that they should be able to measure consistent values.

    Regards,
  • 0 in reply to Jacob Freet
    TI__Genius 11605 points

    Hi Jacob:

    Yes the voltage change means the power supply change from 2.97V to 3.3V to 3.46V, if this will result 8% in gain difference, that explains the split.

    My questions is:

    Is there an optimal Rrssi set to make it works better?

  • 0
    TI__Expert 8070 points
    Hi Naser,

    No the resistor value will just change the measured voltage relative to the resistor value. The RSSI signal is essentially a mirrored current so it is just multiplied by whatever resistor value you choose.

    Regards,