Power supply recommendation, Figure 83, in the AD9691(Rev 0) datasheet,
3.3V Input -> ADP2164 (1.8V) -> ADP125 -> AVDD1_SR
It is normal power supply sequence as I know.
But in the ADP125(Rev D) datasheet,
Input voltage supply range of ADP125 is between 2.3V and 5.5V.
It is NOT include 1.8V.
I wonder I can design as figure 83? ( = ADP125 have more range?)
or I must some modify?
I apologize for this oversight. The LDO in question should be ADP130 or ADP171. Please see link to understand how you can reduce the power delivery network.
Powering GSPS or RF Sampling ADCs: Switcher vs. LDO