Why do we need PHY Interface between DDR Controller and DRAM Memory?

Question

1. Is it required to have PHY in all the systems, if not what happens ?

2. if PHY is removed can we still pull the data from DRAM memory using the DDR controller ? if yes, then why do we need to have PHY Interface.

Answer 1

1. No it's not required. You could set up a wireless connection between them.

2. We can pull data from DRAM when it is connected to a power supply. Each memory cell periodically needs to be refreshed to retain its bit value.