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Comparativa e specifiche sulle Compact Flash Industriali

SLC vs. MLC: An Analysis of Flash Memory


5. SLC and MLC compared

Now that the differences between SLC and MLC have been explained, let’s compare their specifications to help further make a distinction between the two grades.


Table 4: Specification Comparison of SLC and MLC
SLC MLC
Density 16Mbit 32Mbit 16Mbit
Read Speed 100ns 120ns 150ns
Block Size 64Kbyte 128Kbyte
Architecture x8 x8 / x16
Endurance 100.000 cycles 10.000 cycles
Operating Temperature Industrial Commercial

Let’s compare each characteristic in table 4. Using the same wafer size, you can double the density of the MLC Flash by using the charge placement technology. Thus, MLC has greater densities.

The read speeds between SLC and MLC are comparable. Reading the level of the Flash cell compares the threshold voltage using a voltage comparator. Thus, the architecture change does not affect sensing. In general, the read speeds of Flash are determined by which controller is used.

The endurance of SLC Flash is 10x more than MLC Flash. The endurance of MLC Flash decreases due to enhanced degradation of Si. This is a main reason why SLC Flash is considered industrial grade Flash and MLC Flash is considered consumer grade Flash.

Higher temperatures cause more leakage in the cells. Combined with the increased sensitivity required to differentiate between the levels, this leakage will cause the sensors to read the wrong level. As a result, the operating temperature of MLC spans only the commercial range. Leakage is not significant in SLC Flash and thus, it can operate in an industrial temperature range.