Hot!Fastest ADC in smallest MCU?

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abraxas1
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2007/11/09 13:34:06 (permalink)
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Fastest ADC in smallest MCU?

hello,
can anyone tell me what's the smallest MCU with the fastest ADC (10-bits or more)? i'm aiming for 100KHz or better conversion rate, on one or two channels only. possibly just one channel.

better yet, a table or graph describing this relationship would be great. i can't find that info anywhere and it's hard to check all of them out individually...


thanks much!
michael

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    kalpak
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    RE: Fastest ADC in smallest MCU? 2007/11/09 20:26:07 (permalink)
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    Take a look at the 30F series.
    #2
    xiaofan
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    RE: Fastest ADC in smallest MCU? 2007/11/09 20:52:49 (permalink)
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    You may have to look outside Microchip.

    Silabs offer some good and small MCUs with faster ADC. Actually they have the best-in-class built-in ADC for MCUs.
    http://www.silabs.com/tgwWebApp/appmanager/tgw/tgwHome?_nfpb=true&_pageLabel=interactiveGuide&col=adc1
    #3
    Olin Lathrop
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    RE: Fastest ADC in smallest MCU? 2007/11/10 08:23:30 (permalink)
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    can anyone tell me what's the smallest MCU with the fastest ADC (10-bits or more)? i'm aiming for 100KHz or better conversion rate, on one or two channels only.

    100KHz is not that "fast".  A low end 18F should be able to do that, like maybe 18F1320 and related.  The dsPICs have much faster A/Ds, especially in the "power conversion and motor control group".  Check out 30F1010 and related.
    #4
    DarioG
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    RE: Fastest ADC in smallest MCU? 2007/11/10 08:28:26 (permalink)
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    Hi Olin, I seem to remember from a previous thread with somebody, that an average PIC18 (maybe 16 as well) could not take samples faster than 30-35uS circa (including Tad-acq etc). I'm not sure qhich one (if any) allow faster sampling.

    GENOVA :D :D ! GODO
    #5
    Olin Lathrop
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    RE: Fastest ADC in smallest MCU? 2007/11/10 09:44:23 (permalink)
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    Hi Olin, I seem to remember from a previous thread with somebody, that an average PIC18 (maybe 16 as well) could not take samples faster than 30-35uS circa (including Tad-acq etc).

    I just checked my ancient copy of the 18F1320 data sheet, and you're right.  The minimum Tad is listed as 1.6uS.  This says preliminary all over it, but I doubt Tad would get substantially smaller.  I thought there were some 18F with faster A/Ds, but the 18F1320 isn't one of them.  I vaguely remember the 18F with the fast A/Ds were targeted for switching power supply applications.
    #6
    DarioG
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    RE: Fastest ADC in smallest MCU? 2007/11/10 09:49:07 (permalink)
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    Yeah, the infamous "preliminary" wink

    1320 is a low-end device with a difficult life indeed Smile
    Maybe a 2550 or even better a 2553 may perform better?

    GENOVA :D :D ! GODO
    #7
    rhodges
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    RE: Fastest ADC in smallest MCU? 2007/11/10 10:27:03 (permalink)
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    For what it's worth, the 18F45J10 family datasheet (DS39682C, page 327) states a minimum Tad of 0.7 uSecs. The minimum acquisition time is 1.4 uSecs, though, and that is with a source impedance of 50 ohms.
    #8
    nigelwright7557
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    Re: RE: Fastest ADC in smallest MCU? 2018/08/09 14:17:03 (permalink)
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    I found I could get 460,000 samples per second with a PIC18F4550.
    However you have to do a few ADC read cycles before inputting real data or you get glitches on the first part of the data.
    #9
    DarioG
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    Re: RE: Fastest ADC in smallest MCU? 2018/08/09 14:26:27 (permalink)
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    ahem, and "what" do you do with them on such a small PIC? Smile
    (not to mention the 11years gap)

    GENOVA :D :D ! GODO
    #10
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