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Processor with the fastest ADC

Danilo A.
Mastermind 28630 points
Other Parts Discussed in Thread: AM6548, ADS4122, ADC12010

Hi Team,

A customer would like to know the minimum conversion time of our 12-bit ADC which are integrated in our ARM processors. He wants to use a processor with the fastest ADC. Which ARM processor would you suggest?

Regards,

Danilo

  • 0
    TI__Expert 3310 points

    Hi Danilo,

    I can only speak for Sitara processors but a device like AM6548 has 4 Msamples/s max sample rate but there are always caveats associated with ADC measurements (with things like leakage current for example)

    I would advise the customer to ensure that they read and understand all these parameters from the device TRM before trying to implement a solution. If all they are interested in a product is a fast ADC they should normally look at an external ADC product and interface that with one of our processors. 

    We would really need more details about what the intended use case and requirements are before being able to make a proper recommendation.  

    Best Regards,

    Andrei

  • 0 in reply to Andrei Aldea
    Prodigy 20 points

    Hi I replied already in the morning. Shall repeat the same here.

    Our requirement is to digitise 4 pulses of around 5 usec width at 0.1usec ADC and do some computations based the samples.

    PRF of the signals is a maximum of 250 Hz and hence will have enough time to compute the results.

    Using an external ADC may be an ideal solution as suggested by Andrei, but this would require additional interface logic to do a DMA transfer from ADC to internal RAM of the controller. Hence wanted to explore the controllers with built in SAR ADCs.

    Alternately can you suggest us a controller that can support DMA transfer at 40 MHz speed to internal RAM of the controller?

  • 0 in reply to user6464009
    TI__Expert 3310 points

    Hi,

    Those requirements exceed the purpose of any of our SAR ADCs inside Sitara devices. 

    Our processors support several different peripherals that could be used to transfer data with DMA at very high speed but you would need to find a compatible ADC and interface combo as that is more of a systems level question. I would recommend you look at something such as https://www.ti.com/tool/TIDA-01555  (which tops at 1536ksps but is an example) or perhaps the GPMC interface for interfacing with one of our processors. 

    As far as ADC choice is concerned I'm afraid you will have to pose the question to the ADC team and see what combination of ADC and supported interface are available. 

    Do keep in mind when you do select an ADC that accurately detecting a 0.1usec pulse is going to require more than simply a 10Mhz sample rate because of the Nyquist rate as well as more physical limitations caused by internal capacitance and other factors. 

    Regards,

    Andrei

  • 0 in reply to Andrei Aldea
    Prodigy 20 points

    Hello Andrei,

    Thank you for suggestion.

    It is not that we want to capture a 0.1 usec pulse. Our requirement is to sample the 5 usec width pulse with an ADC that has a conversion time of 0.1 usec.

    May be you can redirect the requirement to an A/D expert who can suggest us a 12 bit ADC with better than 0.1 usec conversion time.

    Best Regards

    Dr.Rao.

  • 0 in reply to user6464009
    TI__Mastermind 18095 points

    Dr. Rao:

    If by conversion time you mean sample rate then 0.1 usec corresponds to 10 MSPS.  There are a variety of ADCs that support greater than 10 MSPS to support the need.  The issue is related to the digital interface that is needed.  The ADCs that are faster than 10 MSPS support TTL, CMOS or LVDS interface.  One example of a suitable device is the ADS4122 (12b, 65 MSPS, DDR LVDS or parallel CMOS interface).  Another option is the ADC12010 (12b, 10 MSPS, parallel CMOS or TTL interface).

    --RJH