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Re: STM32L412 ADC Input Specs

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Rick C <gnuarm.deletethisbit@gmail.com> wrote:
> Maybe someone can help me out with this.  I'm looking at the data sheet for the STM32L412xx trying to find details on the mapping of the input voltage range to the 12 bit code produced.  It might appear that the Vref+ and Vref- pins define the exact range, but it seems unusual that it could be equal to the power rails.  With Vref+ = 3.3V and Vref- = 0 volts does 0V on the input produce a code of 0 and 3.3 volts on the input produce a code of 0xFFF and 1.65 volts produce 0x3FF?  
> 
In single ended mode, range is 0V 0 0x000 (+/- offset, non-lineraity, etc) and +Vref = 0xfff. In differential mode, -Vref = 0xfff, 0V =0x800 and + Vref = 0xfff.

> Then there are the input circuits.  Table 75 says Rain is 50 kohm max.  Then table 76 lists Rain max of various values from 100 ohms up.  So do fast conversions really require such low output impedances from the driving circuits?  Table 76 has a column without units indicated, Sampling Cycle @80 MHz.  Any idea what that is? 
> 
> Lastly there is mention of an internal op amp.  Is there any way to insert this between the input mux and the ADC so that every input won't need a driver if we are sampling fast?  
> 
> I'm thinking there must be a document somewhere that explains the ADC in more detail?  
>

There are Applicaton notes. Look at the product page.

Bye

-- 
Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 1623569 ------- Fax. 06151 1623305 ---------

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STM32L412 ADC Input Specs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-23 17:11 -0700
  Re: STM32L412 ADC Input Specs Michael Kellett <mk@mkesc.co.uk> - 2020-07-24 13:13 +0100
    Re: STM32L412 ADC Input Specs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-24 14:13 -0700
      Re: STM32L412 ADC Input Specs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-24 19:32 -0700
        Re: STM32L412 ADC Input Specs Michael Kellett <mk@mkesc.co.uk> - 2020-07-25 20:57 +0100
  Re: STM32L412 ADC Input Specs Uwe Bonnes <bon@hertz.ikp.physik.tu-darmstadt.de> - 2020-07-25 08:38 +0000
    Re: STM32L412 ADC Input Specs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-25 13:09 -0700
  Re: STM32L412 ADC Input Specs Richard Damon <Richard@Damon-Family.org> - 2020-07-25 20:16 -0400
    Re: STM32L412 ADC Input Specs Klaus Kragelund <klauskvik@hotmail.com> - 2020-07-30 08:10 -0700

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