What factors determine the NAND-type flash memory?(3)

What factors determine the NAND-typeflash memory?

 

I / O bits wide

in the past NAND-type flash memory data line is generally 8, but starting from the 256Mb product, there are 16 data lines of products has emerged. However, due to the controller and other reasons, x16 chips relatively few practical applications, but the number will still be upward trend. While x16 chips in the transmission of data and address information is still used when a group of eight, occupied cycle is the same, but when transferring data to 16 bits as a group, doubling the bandwidth. K9K4G16U0M is a typical 64M × 16 chips, which each page is still 2KB, but the structure is (1K +32) × 16bit. Mimic the above calculation, we get the following. K9K4G16U0M need to read a page: 6 command, address cycle × 50ns +25 μs + (1K +32) × 50ns = 78.1μs. K9K4G16U0M actually read transfer rate: 2KB bytes ÷ 78.1μs = 26.2MB / s. K9K4G16U0M need to write a page: 6 command, address cycle × 50ns + (1K +32) × 50ns +300 μs = 353.1μs. K9K4G16U0M actually write transfer rate: 2KB bytes ÷ 353.1μs = 5.8MB / s can be seen, the same size chip, the data line increased to 16 after the reading of nearly 70% performance improvement, write performance is also increased by 16%.

 

Frequency

Frequency of work is very easy to understand. NAND-type flash memory of the operating frequency in the 20 ~ 33MHz, the frequency the more the better performance. In front of the K9K4G08U0M example, we assume that frequency is 20MHz, if we increase the frequency doubled to 40MHz, the K9K4G08U0M need to read a page: 6 command, address cycle × 25ns +25 μs + (2K +64) × 25ns = 78μs. K9K4G08U0M actually read transfer rate: 2KB bytes ÷ 78μs = 26.3MB / s. Can see that if the operating frequency from 20MHz K9K4G08U0M increased to 40MHz, read performance can increase nearly 70%! Of course, the above example is only for the convenience of calculations. Samsung actual product line, you can work at higher frequencies should be K9XXG08UXM, rather than K9XXG08U0M, the frequency of the former current of up to 33MHz.