Pseudo-SLC combines advantages of SLC and TLC/MLC memories - Squaring the circle

01/01/2022 Knowledge

The task of combining longevity and high performance with low costs is like squaring the circle. But this is exactly what pseudo-SLC technology makes possible in flash memories.

Data volumes are growing exponentially in almost all sectors – and with them the demand for storage capacity. Single evel cell (SLC) flash memories are known to offer greater reliability, faster read and write speeds, and longer service life than other memory technologies. However, SLC memories are expensive and have low storage density, making them less suitable for applications that require higher storage capacities. 

Multi level cell (MLC) or triple-level cell (TLC) flash memories, on the other hand, offer high storage density at a lower cost. However, due to their limited durability, they are not suitable for all memory-intensive applications. Pseudo-SLC bridges this gap between the high performance and durability of SLC flash memories and the high density and low cost of MLC/TLC memories.

Higher memory density and durability at a lower cost per gigabyte

To achieve higher memory density and durability at a lower cost, pSLC technology, also known as emulated SLC or quasi-SLC, uses special programming algorithms and voltage levels. These modify the behavior of MLC or TLC flash memories to mimic the characteristics of SLC memories, such as more write/erase cycles, lower error rates, and faster access times. This results in higher reliability and durability without sacrificing memory density. 

The table compares the P/E cycle (prograerase), W/R speed (write/read), and price per GB parameters of various NAND flash technologies for industrial applications.

Industrial NAND Flash Type

Feature

P/E Cycle

W/R Speed

Price per GB

SLC

Single-Level-Cell

Up to 60.000

++++

+

pSLC

Pseudo-SLC

Up to 100.000

+++

++

MLC

Multi-Level-Cell

3.000

++

+++

TLC

Tri-Level-Cell

3.000

+

++++

Table 1: NAND flash technologies in comparison (source: Rutronik)

 

Switching from TLC to pSLC is about three times more expensive for the same memory capacity, since three times the amount of flash memory is required. This makes pSLC significantly less expensive than comparable SLC memories, which are typically used for write-intensive applications and adverse environmental conditions: They cost about ten times as much as TLC memories. pSLC is thus an attractive alternative and the optimal compromise between low-cost TLC and expensive SLC memories, combining longer service life, excellent performance, and temperature insensitivity at a fraction of the cost of true SLC NAND. 

This makes pSLC technology a promising option to meet the changing demands of modern storage systems. It is used in many areas where balancing performance and cost efficiency are essential, such as embedded systems, industrial automation, the automotive industry and enterprise data storage.

With suppliers like Apacer, Swissbit, and Transcend in its portfolio, Rutronik offers pSLC products in all common form factors: SD/microSD cards, Compact Flash/CFast/CFExpress cards, SATA-SSD 2.5/mSATA- SSD/M.2-SATA-SSD (2230/2242/2280)/Slim SATA-SSD, M.2-PCIe-SSD (2230/2242/2280), USB flash drives, embedded USB modules, embedded MMC, BGA-PCIe-SSD. 


For more information and a direct ordering option, please visit our e-commerce platform at www.rutronik24.com.

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Table 1: NAND flash technologies in comparison (source: Rutronik)