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ADS7828: multiple channel acquisition in only one request

laurent cattellat
Prodigy 10 points
Part Number: ADS7828

We are using the ADS7828E chip in order to aquire 8 analog values. We request those values thanks to a I2C link.

We would like to know if there is a way to acquire all the 8 channels input with only one I2C request. 

For the moment, we are making 8 consecutive requests with 8 consecutive answers and we are unable to achieve the sample rate we would like.

If it is not possible, is there a component close to this one (even better if pin to pin compatible !) that would allows us to make all the 8 acquisitions within one request ?

Thanks an best regards,

Laurent CATTELLAT

  • 0
    TI__Mastermind 22950 points

    Hello Laurent,

    Unfortunately, the mux will need to be manually switched via I2C control in order to sample and convert the different channels. I can look into other devices in our portfolio to see if one might fit your simultaneous sampling needs. 

    Moving forward, are there any constrains you have in your system?

    • Is I2C a must for communication or is SPI OK?
    • Are there any specific sampling rate range you would like? 
    • How many channels are required?
    • Resolution? 

    If you can help provide the following information, I can go ahead and find some parts that might be a good fit. 

    Regards,
    Aaron Estrada

  • 0 in reply to Aaron Estrada
    Prodigy 10 points

    Hi,

    Thanks a lot for this prompt answser.

    Unfortunately, I2C is a must...

    - Regarding resolution, we need 12 bits.

    - Number of channels : 8 or more

    - Sample rate : minimum 20 Khz (more is better)

    Best regards,

    Laurent CATTELLAT

  • 0 in reply to laurent cattellat
    TI__Mastermind 22950 points

    Hi Laurent, 

    Unfortunately, we don't offer any simultaneous sampling ADCs with an I2C interface. We only offer SPI and parallel interfaces.  However, we do have the ADS7138. This is a 12-bit, 8 channel device with 140KSPS and I2C interface. While this device does not do simultaneous sampling, there is an auto sequence mode that uses an internal sequencer to switch the mux to the next channel after a conversion. 

    This is ultimately looks like the best fit from our end. Let me know if you have any more questions!

    Regards,

    Aaron Estrada