• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 46 subscribers
  • Views 338 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

VCA 2615 suitability for 16 bit systems

Pavel Haintz
Prodigy 70 points
Other Parts Discussed in Thread: VCA2615, THS4131, ADS1610, THS7530

I am looking at using the VCA 2615 to amplify  a signal with a carrier frequency between 200 kHz and 1 MHz.  This signal would be sampled by a 16 bit A/D converter after the VCA 2615.  In the data sheet it says that it is recommended for 10 and 12 bit systems.  Looking at the data sheet, it should have low enough noise levels and low distortion for a 16 bit system.  Is there any reason that the VCA2615 would limit the performance of a 16 bit A/D converter?

Thanks,

Pavel

  • 0
    TI__Expert 6320 points

    Hi Pavel,

    The output noise of the VCA is louder than the theoretical noise floor of a 14 bit ADC at 4MSPS. Therefore, a 16-bit converter may not buy you anything, depending on your sampling frequency.  Also,  I am currently in the process of verifying the low frequency performance of the VCA.  I know from the datasheet that it will work down to 500kHz, but it is not rated any lower.

    What frequency are you trying to run the ADC at?

    Thanks,

    Chuck Smyth

  • 0 in reply to Chuck Smyth
    Prodigy 70 points

    Hi Chuck

    The signal that I am sampling has a carrier frequency anywhere from 200 kHz to 450 kHz.  The sample rate is four time the carrier, so from 800 kHz to 1.8 MHz.  I am using a board with a ADS1610 Sigma delta converter.  The other option that I am look at is THS4131 followed by a THS7530.  Any other suggestions for a differential amplifier solution that will result in 20 dB to 60 dB of gain?

    Thanks,

    Pavel

  • 0 in reply to Pavel Haintz
    TI__Expert 6320 points

    Pavel,

    I am looking into that today. I should have an answer soon.

    Thanks,

    Chuck Smyth

  • 0 in reply to Chuck Smyth
    TI__Expert 6320 points

    Pavel,

    I have verified that the VCA2615 will work fine down to 50kHz.  Did you have another question?  I don't have any suggestion for another amplifier.

    Thanks,

    Chuck