Kioxia Unveils 2nd Gen XL-Flash Storage Class Memory for Ultra-High-End SSDs

Kioxia has launched its 2nd Generation XL-Flash Storage Class Memory (SCM) that combines the low latency, high performance and capacity of 3D NAND Flash. The new memory devices are designed for ultra-high-end solid state drives and various CXL memory extender devices that need to provide both adequate performance and non-volatility.

Kioxia’s second generation XL-Flash is very different from existing XL-Flash devices. First, the new XL-Flash uses a Multi-Level Cell (MLC) architecture that stores 2 bits per cell (2bpc), as opposed to the existing XL-Flash, which uses a Single-Level Cell (SLC) architecture. I’m here. With MLC, Kioxia is able to increase the capacity of a single Gen 2 XL-Flash device to 256GB (32GB), and up to 2048Gb (256GB) of XL-Flash using up to 8 ICs. It is now possible to build chip packages.

Second, MLC has higher latency than SLC, so Kioxia had to increase the number of planes per device to increase access parallelism and increase peak throughput, partially compensating for the increased latency. The original XL-Flash used shorter bit lines and word lines to improve performance, resulting in 16 planes per device (i.e. the two or more planes used in modern 3D NAND devices for client PCs). (much more than four planes). Anyway, the number of planes per 2nd generation XL-Flash IC is higher than the number of planes per 1st generation XL-Flash IC (i.e. more than 16 planes), so you would not expect an increase in bandwidth per device. Reasonable.