CDCI6214: EEPROM writing power down and VDDREF supply voltage.

Hello,

I've been CDCI6214's datasheet and I have a question about writing to its EEPROM.

In pages 31-32 it explains how to write to EEPROM.

I have a question about a question about step.5 in page 32. It says "Apply 1.8 V to all device supplies. When device operation is not required, only apply 1.8 V to VDDREF". Does it have to be 1.8V? Can't be 2.5 or 3.3V?

My other question is about 3-state inputs (REFSEL and EEPROMSEL). Do both of them have internal pull-up and pull-down resistors? In pin configuration table REFSEL doesn't have the footnote superscript, that's why I'm asking to make sure it has internal pull-up/down resistors.

thanks.