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cha1pi
Level 1
Level 1
5 replies posted 5 questions asked 10 sign-ins

Hello,

For my application I need to use 1.2 Voltage as reference voltage in my TC 397. I see that I can set channel 0 of  a group as an alternate reference which I have done. When doing so, the values from the ADC are incorrect(any value read through the ADC is 4095- Max value for 12 bit). Does the alternate reference ought to be 3.3 or 5 V?

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dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

Hi cha1pi,

After checked with engineers, first, as stated in datasheet, the VAREF range definition is valid for both standard and alternate references.

Second,   when VAREF is too low e.g. 1.5V, at least ADC accuracy will be degraded. This is because with too low VAREF, system noise becomes relatively more dominant. If connect 1.5V to VAREF, are not able to predict ADC accuracy.

dw

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dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

Hi cha1pi,

If refer to datasheet, 5V/3.3V are typical values used for Varef as below:

dw_0-1661227256762.png

 

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cha1pi
Level 1
Level 1
5 replies posted 5 questions asked 10 sign-ins

What about alternate Reference Voltage. What is the minimum voltage for it?

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dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

Hi cha1pi,

After checked with engineers, first, as stated in datasheet, the VAREF range definition is valid for both standard and alternate references.

Second,   when VAREF is too low e.g. 1.5V, at least ADC accuracy will be degraded. This is because with too low VAREF, system noise becomes relatively more dominant. If connect 1.5V to VAREF, are not able to predict ADC accuracy.

dw

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