JEDEC Prepares SPHBM4 Standard to Deliver HBM4-Level Throughput with Reduced Pin Count
JEDEC says it is close to finishing a new memory standard called SPHBM4, short for Standard Package High Bandwidth Memory. The group announced the update on December 11, 2025, and says the spec is still in development.
SPHBM4 is meant to deliver HBM4 class bandwidth while changing how the memory stack connects to the processor. JEDEC says SPHBM4 uses the same DRAM dies as HBM4, but pairs them with a new interface base die designed to be mounted on standard organic substrates. HBM4 stacks are commonly paired with silicon based substrates in advanced packages.
JEDEC Solid State Technology Association, the global leader in standards development for the microelectronics industry, today announced it is nearing completion of a new standard for Standard Package High Bandwidth Memory (SPHBM4). SPHBM4 devices are similar to the HBM4 devices commonly used in artificial intelligence accelerators, using the same DRAM dies on a new interface base die which can be mounted on standard organic substrates. In contrast, HBM4 is typically mounted on silicon substrates.
— JEDEC
The biggest published difference is the signal count. HBM4 uses 2048 data signals, while SPHBM4 is set to define 512 data signals , which is one quarter as many. To keep the same total throughput, JEDEC says SPHBM4 will run at a higher frequency and use 4:1 serialization, so each physical data pin carries more data over time.
That lower pin count is tied to packaging limits. Organic substrates generally need a more relaxed bump pitch than silicon, and JEDEC says SPHBM4 is designed around that reality. JEDEC also points to another potential benefit: organic substrate routing can support a longer channel length between the SoC and the memory stacks, which could allow more stacks in a single package and raise total memory capacity at the system level.
JEDEC did not give a final publication date, and it notes the standard can still change during the approval process. The organization says it will share more details once SPHBM4 is published, and it is encouraging companies to join JEDEC for access to pre publication proposals and ongoing project work.
Source: JEDEC
