----- Original Message ----- 
From: "Mark Rages" <markrages@gmail.com>
To: "Microcontroller discussion list - Public." <piclist@mit.edu>
Sent: Monday, October 02, 2006 7:04 PM
Subject: [PIC] Lower bounds for ADC Vref?


>>  I
>> plan to compensate for this by setting Vref to a low value.  But I'm
>> not seeing anything in the datasheet to tell me how low I can go, or
>> what problems I will see if I go too low.  Noise?  Fixed offset?  Do
>> others have experiences with this?  Am I looking in the wrong place?
>>

Mark,

2.5V

12F675 Datasheet, Table 12-8 parameter A20/A20A and A21.

I'm not sure exactly what you are trying to do (the "low side" comment),
but I don't think your going to get to where you want to be.  You are 
correct
that you will use a small resistor, however you will need to use an op amp 
to
boost the output voltage to something useful.

Ken
________________________________________
"Well that never happened in any of the simulations"
klumia@adelphia.net 


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