ADS131M08: Use internal reference for external SAR

Tobias Lifschitz

Part Number: ADS131M08

Hello,

In our design we would like to connect the internal reference of the device to the integrated SAR ADC of our MCU (EFR32MG12), to save adding another reference. Is this voltage buffered so as to be stable while supplying the current spikes of SAR conversion? Otherwise could we connect a capacitive load to REFIN to supply this instantaneous current?

Thank you!

Tobías

over 4 years ago

0 Alexander Smith over 4 years ago

TI__Guru 55062 points

Hi Tobias,

Our primary support for the device is out today, so I'll ask him to take a second look when he returns next week.

I do not believe this is an intended function of the REFIN pin and I cannot guarantee functionality of the device when used in this way. If you were to do this, I would recommend adding an external buffer and charge bucket capacitor in order to supply the SAR for conversions.

0 Tobias Lifschitz over 4 years ago in reply to Alexander Smith

Prodigy 20 points

Hi Alex,

Thank you for your response. That's what I suspected but wanted to confirm it. In that case we would go for an external buffer or simply use a dedicated reference.

Regards,

Tobías

0 Alexander Smith over 4 years ago in reply to Tobias Lifschitz

TI__Guru 55062 points

Hi Tobias,

I spoke with the designer and he confirmed what I said, a buffer would be required.

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ADS131M08: Use internal reference for external SAR