Can the Low Leakage Mezzanine Board (EVAL-CN0407-1-SDPZ) be separated out from the CN-0407 Circuit Evaluation Board (EVAL-CN0407-SDPZ), to be used separately.

I am undertaking a project in which we have to measure very low level (1pA and above) current.

We did go through the ADA4530-1R-EBZ-TIA evaluation board user guide

and also the reference design - EVAL-CN0407-SDPZ.

The ADA4530-1R-EBZ-TIA evaluation board has a 10Gohm SMT feedback resistor.

The user guide also says about the THROUGH HOLE RESISTOR configuration.

The Circuit Note of EVAL-CN0407-SDPZ says that it has the through hole 10Gohm Glass resistor

on the Low Leakage Mezzanine board (EVAL-CN0407-1-SDPZ).

Since the glass resistor is a hermetically sealed resistor and an absolute requirement for low leakage,

we need the glass resistor in our configuration.

But we don't need the ADC provided with the CN0407 evaluation board.

The dilemma is : We just need the Low Leakage Mezzanine board (with glass resistor)

of the CN0407 evaluation board.

OR

We need the ADA4530-1R-EBZ-TIA evaluation board with glass resistor.

Even though the board is configurable according to our needs, i.e. we can solder the glass resistor,

we do not want to take any risk since it may degrade our low current measurement.

  • 0
    •  Analog Employees 
    on Aug 29, 2017 5:39 PM

    Hi British,

    The answer I received from the CN0407 engineer is written below, hope this helps.

    He will need the ADA4530-1R-EBZ-TIA evaluation board with glass resistor.

    The TIA board comes populated with a 10Gohm glass resistor. One end of the resistor resides on the main board while the other high end is on the mezzanine board.

     

    This photo will give more clarification.

    Vicky

  • Thank you, Brandon.

    I am now confused because of the photo.

    The photo corresponds to CN-0407 Circuit Evaluation Board (EVAL-CN0407-SDPZ) which includes the Data Acquisition Board along with ADA4530-1R-EBZ-TIA evaluation board. I am just interested in the left part of the board which essentially is the "ADA4530-1R-EBZ-TIA evaluation board with glass resistor". I want to know if it is available separately (i.e. only the "ADA4530-1R-EBZ-TIA evaluation board with glass resistor" alone).

  • 0
    •  Analog Employees 
    on Sep 1, 2017 9:00 PM

    Hi British,

    From the documentation that I read in the user guide(http://www.analog.com/media/en/technical-documentation/user-guides/ADA4530-1R-EBZ_UG-865.pdf  ) it appears that the ADA4530-1R-EBZ-TIA can be bought separately from the ADC mezzanine board.  However looking at the BOM, the glass resistor is NOT included with that board, but rather the 10Gohm SMD.(as you pointed out in your original question)

    So your choice is to order the EVAL-CN0407-SDPZ, which will have the glass resistor mounted along with the ADC and accompanying software.  Or you can order the ADA4530-1R-EBZ-TIA, and unsolder the surface mount resistor, and solder in the 10Gohm glass resistor to RF2, and then clean the board once you are complete with the rework.

    Cheers,

    Brandon

  • Thank You Brandon.

    My doubts are almost clarified, unless only if the company can, in certain conditions provide the specific configuration intended for our purpose, by default. Cleaning and Handling is a cumbersome process and we cannot afford to degrade our measurements by doing the alternate process (soldering the glass resistor) imperfectly.
    The photo may provide the idea of the already assembled glass resistor- configuration if available, under any condition.

    .

  • 0
    •  Analog Employees 
    on Sep 5, 2017 5:24 PM

    Hi British,

    I agree that the above picture taken from the user guide might be a bit confusing and misleading.  I think it was probably done as an example of what the board should look like if you were to decide to remove the surface mount resistor and solder in the glass resistor.

    I will give this feedback back to the amplifier team.

    Cheers,

    Brandon