ADC voltage range on PSoC3 (PSoC5)

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JoMa_1461231
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Hi@all,

In a project we use the PSoC3 20bit Del-Sig ADC.

In case no sensor is connected to some sort of input channel of our electronic the value range of the ADC is left and the ADC overflows. It is very clear that there will be no value anymore that makes sense. It's also clear that normally the ADC range shouldn't be left.

We use differential bufferered Mode (Rail-to-rail) in the ADC configuration. VDDA is 5V.

My question is regarding destruction of the ADC block in this case. In the ADC component datasheet (Document Number: 002-22359) on page 38 it is stated that the Input voltage range (differential, buffered) is VDDA - 1 -> in our case 5V - 1 = 4V. Therefore it would be allowed to connect only 4V to the + Input of the ADC. Is this correct or is the differential Voltage between -Input Pin and +Input Pin of the ADC meant here?

How is this related to the ADC Range an page 12 in the same document. There is stated, that the ADC Range (Rail-to-Rail Mode) can be from VSSA+100mV to VDDA-250mV?

Thanks,

jo

1 Solution
Vasanth
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250 sign-ins 500 solutions authored First question asked

Hi Joe,

Exactly. VDDA-1 is the right value to be used. Apologies for the confusion here. We have initiated internal requests to correct the discrepancy between documents and creator.

Best Regards,

Vasanth

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