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Design >> Analog Design >> Hpw much precision voltage ref reqd for DAC/ADC
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Message started by Raj on Nov 1^st, 2004, 9:43am

Title: Hpw much precision voltage ref reqd for DAC/ADC
Post by Raj on Nov 1^st, 2004, 9:43am

The current Bandgap references are designed with such high-order precision say around 1ppm/oC which amount to say 1 mV variation over -40 to 120 oC. But I would like to know how much and it what way would such a small variation can result in the output/bit error of a DAC/ADC. Just bcoz the absolute value of Vref changes, does that mean, there will be overlap of the bit values. Can anybody help me?

Title: Re: Hpw much precision voltage ref reqd for DAC/AD
Post by ywguo on Nov 5^th, 2004, 5:39am

Hi,

I think that relies on your application. Eg., the linearity is important in video application, but the absolute value is not so important. :)

Yawei

Title: Re: H0w much precision voltage ref reqd for DAC/AD
Post by rpaul on Nov 9^th, 2004, 4:04am

Ok if I assume that in most cases , the absolute value doesnot matter much ( since it can be trimmed down .....I have some doubt here also) then , why does the variation in temperature of such high order say 1ppm/Celcius can affect the systems. Can anybody site an example or direct me to some materials regarding this.