Use this PDF alongside your datasheet from Micron or Samsung to see how manufacturers implement these industry-wide standards. Available for free at JEDEC.org! Which platform are you planning to post this on?
Before the JESD79-4D PDF existed, memory modules from different vendors could not reliably work together. The standard ensures that a DDR4 chip from Samsung, SK Hynix, or Micron behaves identically in terms of protocol, timing, and electrical signaling.
: Employs a Pseudo Open Drain (POD) 1.2V I/O interface to improve signal integrity while reducing power consumption. Key Features and Improvements
JESD79-4D introduced enhancements like the Pseudo Open Drain (POD) interface and bank groups . Bank groups allow for faster data access by enabling simultaneous operations across different sets of banks. JESD79-4D vs. Later Generations
: Translating high-level read/write commands into strict physical sequences (RAS, CAS, WE, ACT).