HiI am interested in Terasic ADA Daughter Card for DE1 Development Board (see link below) http://www.terasic.com.tw/cgi-bin/page/archive.pl?language=english&categoryno=39&no=278 I have asked about proforma invoice but they didn't responde and i don;t know why. :confused: At this moment card is out of stock. Do you know where else I can buy these card? Best regards
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.
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
HelloI 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
HelloHis 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
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.
HelloThe 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.
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
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.
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
For DAC channel A, you can remove T5 and add a zero ohm jumper for R60. You get a 50 ohms DC coupled single ended output.An AD8132 or AD8138 could be used in a circuit according to the AD9248 datasheet. But there's neither a suitable place on the board nor a differential connector option to place it external to the board. So it must be glued to the board. It's possible to my opinion, but I don't want to suggest it generally.
Ok, I understand the DAC end. ThanksAs for the ADC end, I think I have to try to do it. So where on the board is the best place to put in the signal? At R4 (for ch. A)?? I am assuming that the signal should be at Vin+. Is this correct? And you say that this signal need to have a 1.5V bias?? I think it should be possible to use an op amp but I it is also quite simple for me to add a 1.5V DC bias to my signal. Do you think this would work?? Have I misunderstood? Thanks again for your invaluable help.
I suggest to read the ADC datasheet regarding suggested options for DC input signals. I mentioned a true differential driver, which is the best option in terms of supressing common mode interferences and also achieves best ADC linearity.A single ended configuration would e.g. remove R1, C1 and T2, connect left side of R5 to VNCT_A and left side of R4 to input jack. The input voltage range is 0.5 to 2.5 then.
Hi,I have decided to opt for the using a differential amplifer for the ADC input but am unsure about how to attach it to the board due to it's small size. Would you advide using the evaluation board? (EVAL-ADDIFFAMP)?? http://www.analog.com/en/amplifiers-and-comparators/operational-amplifiers-op-amps/eval-addiffamp/pr... It appears to have SMA input/output. In this case I can just connect it to the board and make the adjustments to get single ended configuration to prevent the DC blocking from the capacitor and transformer? Does this sound feasible?? Thanks
--- Quote Start --- I suggest to read the ADC datasheet regarding suggested options for DC input signals. I mentioned a true differential driver, which is the best option in terms of supressing common mode interferences and also achieves best ADC linearity. A single ended configuration would e.g. remove R1, C1 and T2, connect left side of R5 to VNCT_A and left side of R4 to input jack. The input voltage range is 0.5 to 2.5 then. --- Quote End --- Thanks for the info. I tried to implement this single ended configuration but was unsure of a few aspects. I removed R1 C1 and T2 and connected R4 to the input jack so that now the SMA input is connected the VINpA pin of the AD9248 by only the 33ohm resistor R4. I assume this to be correct The problem is where to connect R5 to VINCT. To the pad of the removed transformer T2 or directly to the bridge between R2 and R3?? Also, by left side I assume you mean left side on the schematic, i.e input jack side as opposed to ADC side. I hope I can get this working as the DAC side works perfectly. Unfortunately there is very little useful info on the AD9248 or terasic board data sheets about configuring for single ended ADC operation Thanks Ben.
Hi,I desolded the DAC transformer on a EP2C70dsp card and I have now frequency from 1mHz to 1MHz. I am interested in buying one terrasic ada daughter card. Before, I would like to see the schematic. Where can I find this shematic ? Thanks
No value printed means, they are not present in the standard version. I think, they are intended as assembly option to be used instead of the transformer for DC capable output. However, I dodn't understand the purpose of two resistors.