What factors determine the NAND-type flash memory?(1)

What factors determine the NAND-type flash memory?

 

Number of pages

as already mentioned, the greater the capacity of flash memory pages the more pages the greater the longer address. But this time is not linear, but a one step change. For example, 128,256 Mb 3 cycles of the chip need to send address signals, 512Mb, 1Gb needs 4 cycles, and 2,4 Gb needs 5 cycles.

 

Page capacity,

the capacity of each page determines the amount of data can be transferred once, so large volumes of pages have a better performance. Mentioned earlier, large-capacity flash memory (4Gb) increased page capacity, increased from 512 bytes to 2KB. Page is not only easy to improve the capacity to improve the capacity of flash memory can 8gbit to improve transmission performance. We can note examples. To Samsung K9K1G08U0M and K9K4G08U0M, for example, the former is 1Gb, 512-byte page size, random read (stable) time 12μs, writing time is 200μs; latter 4Gb, 2KB page size, random read (stable) time 25μs, the time to write is 300μs. Assuming they work at 20MHz.

 

Read performance

NAND-type flash memory into the read steps: addressing information to send commands and data transmitted to the page → Register (random read settling time) → data came (a week of 8bit, need to send or 2K + 512 +16 64). K9K1G08U0M need to read a page: 5 commands, addressing cycle × 50ns +12 μs + (512 +16) × 50ns = 38.7μs; K9K1G08U0M actually read transfer rate: 512 bytes ÷ 38.7μs = 13.2MB / s; K9K4G08U0M read a page need: 6 command, address cycle × 50ns +25 μs + (2K +64) × 50ns = 131.1μs; K9K4G08U0M actually read transfer rate: 2KB bytes ÷ 131.1μs = 15.6MB / s. Therefore, the use of 2KB page size than 512 bytes of read performance capacity increases by about 20%.