ADS131M08: External Reference Range

Hi Colin,

welcome to our e2e forum and thank you for your interest in our data converters.

You are reading the ADS131M08 datasheet correct. The device does unfortunately not allow the connection of an external 2.5V reference.
You may want to look at the ADS131E08 instead if you are looking for an 8-Ch, simultaneous sampling ADC that allows the use of an external 2.5V VREF.

Regards,
Joachim Wuerker

Ah okay thank you!

Maybe i should open a new thread, but somewhat related question. The datasheet says there's a negative bias generator from a charge pump internally. However, there's no pins for an external cap as most charge pumps would require. Any chance there's a way to get access to this negative voltage bias? Would be such a nice feature if that was pulled out so that external op-amps could output true zero without the need for another IC.

Hi Colin,

the caps for the internal negative charge-pump are all internal. Unfortunately there is no external access to the output of the charge pump. But this is good feedback for future devices.

Regards,
Joachim Wuerker

Thank you Joachim!

I was pretty sure I knew the answer, but you never know for sure. Seems like pin 27 is just begging for something to do! Instead I'm going to have to use something like the LM7705, but doubtful I have the board space for that. Hope you guys add this in the future, would be a great addition to this part in my oppinion.