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PGA970: PGA970 ADCs and demodualtors

Piyusha
Prodigy 110 points
Part Number: PGA970

Hi, 

The PGA970 datasheet says that the IC chip conditions upto 2 differential secondary-side waveforms through the 2 24-bit ADCs with digital demodulators.

So if I have connected the secondary coil wires of our LVDT to the S1N and S1P  pins of PGA970 chip then does that mean that only S1 ADCs and demodulators are 'ON' and the S2 ADCs and demodulators are not functioning at that moment? (S1 Gain is configured to differential mode). 

Also why two different ADCs and demodulators are given? What is the function of two different paths and will only one path suffice? 

Thank you, 

Piyusha 

  • 0
    Prodigy 110 points

    Also, what is the use of the rectifier if the signal as already been converted to DC after the ADC stage (before it is fed into the bandpass filter) ?

    Thank you,

    Piyusha

  • 0 in reply to Piyusha
    TI__Mastermind 31655 points

    Hi Piyusha,

    The 2 ADCs and demodulators are are individually enabled. If you are not using one, you can leave it disabled so that it will not be running and drawing power.

    Typically with an LVDT the two secondaries are measured separately. The purpose of this is to determine the phase information that is used to find the position of the LVDT relative to the center/zero position.

    The signal coming out of the ADC and into the bandpass is still an AC signal.

    Regards,