• RE: Different specification on AD7691

    Hi Solar,

         This may create confusion but the AD7691 is an 18 bit ADC and need to do correction on the wiki page. I'll check and get back to you on the AD7691 SNR performance at lower reference.

    Regards,

    Jonathan

  • AD7691: Vref

    Q 

    Question on AD7691: What should be Vref to convert of the maximal number of
    bits a difference between two signals which a little from each other differ?
    For example, Vin + = 4,5V, Vin-= 4,49V.

     

    A 

    As the absolute input range max is =Vref…

  • RE: Code Snippet SPORT Setup

    We tried to translate your query to English using Google translator and understand that you query is,  "Is it possible to get a snippet code with the EVAL-SDP-CB1Z SPORT setup intimately combined with an AD7691-EVAL board?".

    >> Unfortunately…

  • RE: ADM7150 as reference supply for AD7691

    Hi,

    We do not generally recommend LDOs to supply the REF pin since it does not have the ability to sink current. It may work, but the only way to know for sure is to test it. The AD7691 is proven to work well with ADR435, it's the recommended reference…

  • RE: wrong conversion with AD7691

    Hi Denis,

    Thanks for the feedback. On the Ref pin of the AD7691, datasheet recommends to use the AD8031/32 buffer as it is proven as ref inputs for the AD7691 and it is recommended to put a 10uF capacitor on the Ref pin to make the Reference stable.…

  • RE: Looking for product longevity advice (Roadmap) with integration of Linear Tech

    Hi Phil,

    The AD7691 is part of a 10 pin SAR family that are pin and package compatible. You can see this in the parts table in the AD4003 datasheet (table 8). The most recent release in this 10 pin compatible family is the AD4003 which was released last…

  • RE: Understanding common mode voltages with true differntial ADC

    Hi Haw,

    In your example the ADC (AD7691) would not function correctly as the ADC expects the common mode voltage to be 2.5V with a 5V ref and with 3.5V and 4V on the inputs the common mode voltage is (3.5V+4V) / 2 = 3.75V. This is too far from 2.5V.…

  • Repeated samples from AD7691

    I am currently testing the AD7691 18-bit SAR ADC. I have made a circuit with a 16-bit DAC that puts out a voltage for the AD7691 to sample. Then I programmed a micro controller to read and write bits to the DAC and ADC with SPI, and a serial port to transfer…

  • Stuck codes in samples from ADC

    I am currently testing the AD7691 18-bit SAR ADC. I have made a circuit with a 16-bit DAC that puts out a voltage for the AD7691 to sample. Then I programmed a micro controller to read and write bits to the DAC and ADC with SPI, and a serial port to transfer…

  • AD7691 SDO status on Power Up

    We are using 2 AD7691 in 4 wire CS mode with 4 flash memory ICs using the same SPI bus, these 2 are connected to a TI TPS430 u Controller.  The power to the ADCs/flash is controlled by a FET and the TPS430.  The SDO pin on the ADCs is tied low after power…