ADS8688AT: Regarding input voltage range for an ADC

Santhosh Kumar S

Part Number: ADS8688AT

Hello Everyone,

I am using ADS8688ATDBT in my design for converting Analog DC Voltage to Digital values. In the datasheet I found that the internal reference voltage for ADC IC is 4.096V.

In my design Input DC voltage is ranges from 0 to 6V. I am attenuating the input to 0 to 4.5V DC & giving to ADC IC as an input.

Is that ADC is capable to convert whole range i.e. 0 to 4.5V ? or Do I need to attenuate the input signal still to get 0 to 4V (as internal reference of ADC IC is 4.096) ?

Please clarify my question.

Thanks

Santhosh

over 3 years ago

0 Dale Li over 3 years ago

TI__Mastermind 35590 points

Hi Santhosh,

ADS8688AT is able to capture 0~4.5V signal, actually each channel can be configured to any of the following ranges (Channel-Independent):

– ±10.24 V, ±5.12 V, ±2.56 V, ±1.28 V, ±0.64 V

– 10.24 V, 5.12 V, 2.56 V, 1.28 V

Regards,

Dale

0 Santhosh Kumar S over 3 years ago in reply to Dale Li

Intellectual 500 points

Hi Dale,

But Internal Vref is 4.096V right? It means ADC can able to convert maximum input of 4.096V if I am not wrong.

+1 Dale Li over 3 years ago in reply to Santhosh Kumar S

TI__Mastermind 35590 points

Hi Santhosh,

There is an analog front-end(AFE) including PGA integrated on each channel, this is different from most precision ADCs. The input signal is scaled down to a certain signal level for the ADC code. I have listed all ranges which are supported on ADS8688AT, the 4.096V is not supported.

Regards,

Dale

0 Santhosh Kumar S over 3 years ago in reply to Dale Li

Intellectual 500 points

Hi Dale,

Thanks for your answer.

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ADS8688AT: Regarding input voltage range for an ADC