MLCs

MLC stands for multi-level cell, a type of non-volatile flash memory in which each memory cell stores more than one bit of data by using multiple threshold voltage levels. In the most common implementation, an MLC stores two bits per cell by supporting four distinct threshold states, with the two-bit value mapped to those states by the memory controller. This approach increases data density compared with single-level cell (SLC) memory, which stores one bit per cell. Other density families include TLC (three bits per cell) and QLC (four bits per cell).

The primary advantage of MLC is lower cost per bit and higher storage density, enabling higher-capacity flash devices such as solid-state drives, USB flash drives, and memory cards. The trade-off is reduced endurance and data-retention characteristics relative to SLC, and generally greater susceptibility to errors as the number of states per cell increases. To maintain data integrity, devices rely on stronger error correction codes (ECC), wear leveling, and refresh or scrubbing routines, as well as careful controller design and firmware management.

MLC implementations appear in both planar and 3D NAND technologies, contributing to the widespread use of flash memory in consumer and enterprise storage. As memory scaling continues and higher bit-per-cell configurations become common, engineering efforts focus on improving endurance, reliability, and error management to balance cost, performance, and lifespan.

Note: The acronym MLC can have other meanings in different fields, but in the context of flash memory and storage, it denotes multi-level cell technology.