SLC and MLC technical analysis

Five authorized agents - original - spot technical support

What is SLC?

SLC English full name (Single Level Cell - SLC) is a single layer storage. Mainly used by Samsung, Hynix, Micron, Toshiba, etc.

The SLC technology is characterized in that the oxide film in the floating gate and the source is thinner, and the stored charge is removed by applying a voltage to the charge of the floating gate when writing data, and then passing through the source. In this way, one information unit can be stored. This technology can provide fast program programming and reading. However, this technology is limited by SILICon efficiency and must be processed by more advanced process enhancements. ), in order to improve the SLC process technology.

What is MLC?

MLC English full name (Multi Level Cell - - MLC) is multi-layer storage. Mainly used by Toshiba, Renesas, Samsung.

Intel first developed the MLC in September 1997. Its role is to store two units of information in a Floating Gate (the portion of the flash memory cell where the charge is stored) and then use different potentials. Precise reading and writing by voltage control stored in the memory. MLC uses a large number of voltage levels, each unit stores two bits of data, and the data density is relatively large. The SLC architecture has two values ​​of 0 and 1, and the MLC architecture can store more than four values ​​at a time. Therefore, the MLC architecture can have a better storage density.

Compare the advantages of MLC with SLC:

Signed in the current market mainly based on SLC and MLC storage, we know more about SLC and MLC storage. The SLC architecture is 0 and 1 values, and the MLC architecture can store more than 4 values ​​at a time. Therefore, the MLC architecture has a high storage density and can use the old production process to increase the capacity of the product without additional investment in production equipment. Have the advantage of cost and yield.
Compared with SLC, MLC has lower production cost and large capacity. If improved, the read and write performance of MLC should be further improved.

The disadvantages of MLC compared to SLC:

The MLC architecture has a number of shortcomings. First, the lifetime is short, the SLC architecture can access 100,000 times, and the MLC architecture can only withstand about 10,000 accesses.

Secondly, the access speed is slow. Under the current technical conditions, the theoretical speed of the MLC chip can only reach about 2MB. The SLC architecture is more than three times faster than the MLC architecture.

Furthermore, MLC consumes more energy than SLC and consumes about 15% more current than SLC under the same conditions of use.

Although MLC has many disadvantages compared with SLC, MLC still has an absolute advantage in terms of single chip capacity. Due to the absolute advantages of MLC architecture and cost, it can meet the market demand of 2GB, 4GB, 8GB and even larger capacity in the future.

Identification of SLC and MLC:

First, look at the transmission speed. For example, there are two products that use the RockChip chip. The test speed should be 2 or 3 times the SLC, and the slower speed is the MLC. Even MP3s that also use the USB 2.0 high-speed interface cannot change the shortcomings of slow MLC writes.

Second, look at the FLASH model

In general, the Samsung flash memory with K9G or K9L as the starting model is MLC, and the modern flash memory with HYUU or HYUV as the starting model should be MLC. The specific chip number is Samsung and Hyundai as an example: Samsung MLC chip number is: K9G****** K9L*****. The modern MLC chip number is: HYUU**** HYUV***

Simple summary:

If MLC is an emerging flash technology, then its "new" is only reflected in: low cost!

Although MLC's indicators are behind the SLC flash. However, MLC wins SLC in architecture, MLC is definitely the future development direction, and there are quite a few solutions to the problem of MLC transmission speed and number of reading and writing, such as Samsung master chip, wear leveling technology, 4bit ECC school. The inspection technology can also get good results when using the MLC chip. Its performance is no different from that of using the SLC chip, and it will save a considerable amount of cost.