The storage units are divided into two categories: SLC (single-level cell monolayer) and MLC (multi-level cell multilayer). In addition, SLC flash memory has the advantage of 100,000 replication times, up to 10 times times higher than MLC flash memory. In addition, in order to ensure the life of MLC, the control chip is calibrated and the intelligent wear balance technology algorithm, so that each memory unit can be allocated to the average number of times, to achieve 1 million-hour failure interval (MTBF).
MLC and SLC two architectures now there is a widespread misunderstanding, that is that the MLC architecture of the NAND Flash is the Liepin, only the SLC architecture of NAND flash memory can be assured in quality. But the use of MLC architecture NAND Flash products in 2003 has been put into the market use, has not seen which user said they have purchased large capacity CF, SD card has quality problems. Perhaps you will say that this is temporary, there will be problems in the future, then we will first recall the development of MLC and SLC's current development and then to give the hypothesis to the conclusion.
SLC technology, the principle of access to the SLC architecture is 0 and 12 charge values, that is, each cell can only access 1bit data, a bit similar to the switching circuit, although simple but very stable. Like the CPU parts of a computer, to accommodate more transistors in a certain volume, it is necessary to increase the level of production technology and reduce the volume of a single transistor. At present, SLC technology is limited by the low silicon efficiency problem, if we want to improve the process technology, we must adopt more advanced technology, which means that the manufacturer must replace the existing production equipment, the investment is not said and it is a bottomless pit. The MLC architecture can store more than 4 charge values at a time, so have a better storage density, plus the use of existing production equipment to improve product capacity, manufacturers that enjoy the advantages of production costs while product yield is guaranteed, naturally more popular than the SLC architecture.