VDD for LS1046

[Ellu24]

As per reference design, PF8100 is not used for providing CPU_VDD(0.9/1v) and is provided using another buck converter LTC 7150 which is highlighted in the attachment. My question is that:

1) Is it necessary to provide another regulator , that is LTC 7150 or can I use PF8100 itself for VDD?

Please find the attachment.

Thanks in advance