Inquiries about EXT_CAP of AD5271

Inquiries about EXT_CAP of AD5271

 

Hi all,

For circuit reasons, we are using the AD5271 with a voltage of Vdd:3.300V and Vss:-1.720V.

 

We are using only RAM because writing to ROM does not work well, probably due to Vss.

I am using RAM only.

 

So, please tell me about the following.

・ If the EXT_CAP pin is not used, what potential should it be fixed at?

 

If it is used for a charge pump, I think OPEN is better, but what do you think?

 

Best Regards,

Takahiro