Forum Discussion

25 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    Who did you ask to? Directly to Terasic Technologies? Altera distributors should have some stock of these board, so you may ask to your local Altera distributor.

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    I have asked Terasic directly. Altera distributors in Poland don't sell development kits for individual users, only for companies. Maybe I will find some distributors in neighbouring countries.

    Thank you for response

    Best regards
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    Hello

    I am looking a user of these board. I have problems with these daughter card. Resistance between VCC33 (3.3 Volts) and GND pins are very low (56 Ohms) and DA converter temperature rising after power on. I have found that my board is assembled different than it is decsribed on schematic. So I don;t know what to do, but I cannot exclude that these behavior is my fault:( .

    Best regards
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    Hello

    His temperature rising very fast after power up (just few seconds). The temperature isn't very high (I could touch him- DA don' scald). I could try to measure temperature, but I don't want to overstress my evaluation board. Besides it will not solve my problem.

    Best regards
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    I've one of terasic's ADA board and it only has a HSMC expansion board ( for using with their DE3 ). so you can't plug them to the DE1 nor the DE2 boards.

    P.S. it doesn't get so hot. but I didn't give any high freq. signal to it yet.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    Hello

    The problem has been solved. Source of the problem was 40 pin expansion connector - if we plug ADA board "uncorrectly" we will have "higher" resistance on connection between evaluation and expansion boards. My application works on maximum frequency of D/A converter (125 MHz). For some signals I have to set current strength (for output buffers) about 12 mA or 16 mA to obtain required 3.3V amplitude on digital bus.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Hi,

    I am using one of these Terassic ADA boards but really need to DC couple the input and output signals but notice that at least the input is AC coupled (with 0.1uF capacitor). Does anyone know if it is possible to DC couple the input ot at least change the capacitance/resistor value to reduce the time constant?

    The amplitude of my input signal can change sharply (close to square wave) and I need to avoid the distortion caused by charging and discharging of the capacitor.

    Thanks.

    Ben
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Curiously, Terasic didn't feel a need to specify a frequency range for the AC-coupled AD and DA. By mini-circuits transformer datasheet, it's 0.4 MHz (-3dB) respectively 1 MHz (-1dB). The DA output can be changed to single-ended by removing the transformer and installing a jumper instead. For the AD inputs, that have a double transformer coupling, there's no easy way, cause the AD inputs must be biased around 1.5V. Single ended operation is possible with some performance degradation, but the level shift is necessary. The best solution would be a true differential amp as AD8132.

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Thanks,

    I have thougth about my requirement and concluded that without beng able to use single ended operation/DC-coupling (Are they the same thing) then I cannot use it for my application. Hence, I would be grateful if you can help me out with the following questions:

    1. From the schematic it is not clear to me where to install the jumper and , is it possible for you to provide more details on this?? IT is possible I can live live with the DAC part being AC coupled but the DAC part really has to be.

    2. Is there any other AD/DA board that is compatible with the Cyclone II starter kit and allows DC-coupled inputs?

    3. Is it possible combine the AD8132 amplifier that you mentioned with the Terasic ADA board?

    Thanks again

    Ben