It was discovered yesterday that Samsung Electronics is pushing forward with a plan to change the integrated circuit (IC) of the low-power DRAM (LPDDR) that goes into Apple’s iPhone to a discrete package method. It has been reported that the relevant development organization has begun research. It has been reported that this was done at Apple’s request, reports The Elec. 

Apple plans to transition to a separate package that places LPDDR for iPhones independently from system semiconductors starting in 2026. This is because memory bandwidth expansion is inevitable in line with the launch of on-device AI and foldable phones. Previously, the method was a package-on-package (PoP) method that stacked LPDDR vertically on top of system semiconductors.

Apple introduced LPDDR starting with the iPhone 4 in 2010. LPDDR is based on PoP, which vertically stacks memory on top of a system-on-chip (SoC). PoP is mainly used in mobile devices because it can design IC sizes smaller than horizontal packaging.

The problem is that PoP is not suitable for on-device AI devices. Bandwidth is the product of ① data transfer rate, ② data transfer parallel width (bus width), and ③ the number of data transfer channels. In particular, ② and ③ are determined by the number of input/output pins (I/O pins) of the memory. If the number of I/O pins increases, the package size must increase. However, since PoP determines the memory size according to the SoC, the number of I/O pins is inevitably limited. This limits the bandwidth.

The discrete method also has advantages in thermal management. On-device AI generates considerable heat because it performs large-scale parallel calculations. In PoP, the path for heat dissipation is limited by the single-layer structure, whereas in the discrete method, not only is the surface area for heat dissipation wide, but the heat generated from the SoC and memory does not overlap.

Samsung Electronics is likely to apply the next-generation memory standard LPDDR6-PIM for iPhones. LPDDR6 is estimated to have data speed and bandwidth that are 2-3 times higher than the previous generation LPDDR5X, and PIM is a 'processor-in-memory' that performs calculations within the memory.

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In short, this standard is exclusive to on-device AI. Since the beginning of this month, Samsung Electronics and SK Hynix have been working together to standardize LPDDR6-PIM as soon as possible.