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ADS7067: Datasheet Information on Acquisition time

Dardan Kolukaj
Prodigy 400 points
Part Number: ADS7067
Other Parts Discussed in Thread: ADS7066, OPA320

Tool/software:

Hi all,

Looking at the Datasheet of ADS7067, wee see in Chapter 6.6 Timing Requirements an Acquisition Time of 300ns

Looking at Ch 8.2.2.1 at the Calculation it states 800ns instead of 300ns

--> Is the calculation correct? Would the OPA235 still have enough Bandwidth and fit the Application? Will there also be an EVM available for ADS7067?

Appreciate your support,

Dardan

  • 0
    TI__Expert 3850 points

    Hello Dardan, 

    Thank you for bringing this up, I will talk to the team and make sure we correct this on the datasheet. 

    In the calculation it should be 300ns instead of 800ns, with that difference the BW should needed should be closer to ~18.7MHz. The recommended opamp on the datasheet and the evm is the OPA325, which wouldn't be enough to run with the full bandwidth/sampling speed. The OPAx350 that you mentioned, however, does have the bandwidth capabilities for the ADS7067. 

    As far as the EVM, the ADS7066 and ADS7067 are pin to pin compatible, the only difference between them is the sampling speed, which means that the device can be replaced and evaluated using the same board. It would still be limited to the bandwidth of the ADS7066 though. Since the parts are so similar there is no plan to make another EVM board for the ADS7067 at the moment. 

    If I may ask, what kind of set-up would this higher bandwidth evm be needed in? or helpful in? 

    Best regards, 

    Yolanda 

  • 0 in reply to Yolanda Gonzalez
    Prodigy 20 points

    Hi Yolanda,

    thanks for your reply. It is very helpful for us. 
    Can you please also recommend an opamp (ADC buffer) with less current consumption for this ADC? We are searching something less then 1mA with that bandwith. 

    Best regards,

    Michael 

  • 0 in reply to Michael Daude
    TI__Expert 3850 points

    Hello Michael,

    I apologize for the delay, I was out of the office for a few days. The closest I could find that had the bandwidth as well as the low current was the OPA320, with an IQ of 1.45mA/Ch and BW = 20MHz. Could this work?  What kind of power budget do you have in for your system? There are other ADCs that consume more power but have an integrated driver in them if you are interested?

    Best regards, 

    Yolanda

  • 0 in reply to Yolanda Gonzalez
    Prodigy 20 points

    Hello Yolanda,

    our design is ready for production at the moment. Thus a new ADC isn't an option. So, we will try several opamps with higher bandwith. 

    Thanks for your suggestion of the OPA320. 

    Thanks for your support!

    Best regards,

    Michael

  • 0 in reply to Michael Daude
    TI__Expert 3850 points

    Thank you Michael!  Happy to help!

    Best regards, 

    Yolanda