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Please suggest a suitable differential amplifier for ultra low voltage signal (-3mV)

esha eesha
Prodigy 20 points
Other Parts Discussed in Thread: THS4521, THS4524, THS4522

Hi,

I request your suggestion for proper IC selection for very low voltage signal amplification. I am getting a signal (a negative going pulse of about 10ns width and voltage of -3mV) from a sensor/detector.  I want to amplify the signal by 10 or 20dB and also like to get differential output signals like +3mV*Gain, and -3mV*Gain.

Thank You...

  • 0
    TI__Mastermind 25825 points

    Hello esha,

    In order to help you further, we need to understand your system in more detail. Therefore, please answer the following questions:

    1) What is the sensor you're interfacing with?
    2) What power supplies do you have available?
    3) 20dB gain is 10V/V. Therefore your -3mV signal will be amplified to -30mV. What is the output of the amplifier connected to?
    4) What are the rise/fall times of the 10ns pulse? Is it rectangular? Is it periodic? If so, what is the period?
    5) Are you looking for a true differential output (like the THS4521)?
    6) Can you share your schematic and/or system block diagram?

  • 0 in reply to Pete%20Semig
    Prodigy 20 points

    Hi Pete Semig,

    Thank you for your quick response.

    1)What is the sensor you're interfacing with?

    Its a charge particle detector. for more information you can check the link below.

    http://www.nevis.columbia.edu/~chi/rpc/cms-rpc-tech-note.pdf

    2)What power supplies do you have available?

    Design is still at initial state, so power supply is not a problem. We will use regulated power supply.

    3)20dB gain is 10V/V. Therefore your -3mV signal will be amplified to -30mV. What is the output of the amplifier connected to?

    We are more concerned about getting the differential signal. gain of about 80 to 100dB would be file that is about (+0.3V and -0.3V). 10 or 20dB is for our internal testing.

    4)What are the rise/fall times of the 10ns pulse? Is it rectangular? Is it periodic? If so, what is the period?

    We get back to about the rise time and fall time. for pulse shape please go though the following link.

    http://aliceinfo.cern.ch/Public/Objects/Chapter2/DetectorComponents/TOFPrinciple.gif

    http://inspirehep.net/record/825975/plots (2nd image)

    pulses are not periodic.

    5)Are you looking for a true differential output (like the THS4521)?

    yes. Since signal is of very low voltage, Kindly suggest us how to proceed with schematics and PCB design. (like in

    which layer signal should be routed, restrictions on number of vias, is ground shielding required for signal lines

    etc.) 

    6)Can you share your schematic and/or system block diagram?

    If possible will share the block diagram with you. Need to check on that.

     

    Thank You...

  • 0 in reply to esha eesha
    TI__Mastermind 25825 points

    Hello esha,

    Thank you for the additional information. Now that I understand your application in more detail, I'm going to move it to the high-speed amplifier forum.

  • 0 in reply to Pete%20Semig
    TI__Genius 15975 points

    Hi esha,

    Based upon the pulse shape provided and the rise/fall curves in the fig: http://inspirehep.net/record/825975/plots (2nd image), the THS4521 should work proper for the application as shown in the plot. Do you think the rise/time and fall times of the waveform would be the same as shown in the above plot?

    The THS4521 being able to operate the input common mode below negative rail upto -0.1V (max) should help for ground referenced signals. There is also an option of upgrading to THS4522/THS4524 in case more anode pick-ups are to be sensed.

    As shown in fig: http://aliceinfo.cern.ch/Public/Objects/Chapter2/DetectorComponents/TOFPrinciple.gif, it seems to me that the sensing could be done using differential signals as well. I understand that there are various ways of sensing, but it would help the system if it were differntial sensing in which the signal swing is doubled. It might as well be helpful to share the schematic and block diagram.

    Best Regards,

    Rohit