Dear member of SanDisk Community, welcome.
1- [ SDSDQM-008G-B35 (8GB microSDHC card). We would like to know if this is SLC/MLC/TLC type? ]
2- [ Does the above card fall under the more reliable SLC category? ]
2.1- _ SLC Flash is used in commercial and industrial applications that require high performance and long-term reliability._
Some applications include industrial grade Compact Flash cards or Solid State Drives (SSDs).
2.2 - Traditionally, each cell has two possible states, so one bit of data was stored in each cell in so-called single-level cells, or SLC flash memory.
SLC memory has the advantage of faster write speeds, lower power consumption and higher cell endurance.
However, because SLC memory stores less data per cell than MLC memory, it costs more per megabyte of storage to manufacture.
Due to faster transfer speeds and longer life, SLC flash technology is used in high-performance memory cards.
2.3- It is important to understand what makes up a Flash cell, before explaining the variation between SLC and MLC Flash.
Each cell consists of a single transistor, with an additional “floating” gate that can store electrons.
A large voltage difference between the drain and the source, Vd – Vs, creates a large electric field between the drain and the source.
The electric field converts the previously nonconductive poly-Si material to a conductive channel, which allows electrons to flow between the source to the drain.
The electric field caused by a large gate voltage, Vg, is used to bump electrons up from the channel onto the floating gate.
As an electron travels closer to the drain, it gains more momentum and thus, more energy.
But, this amount of energy is not enough to push an electron onto the floating gate.
Electrons with high momentum near the drain can sometimes bump into Si (Silicon) atoms .
This bump gives the electron enough energy to be pushed onto the floating gate.
The number of electrons on the floating gate affects the threshold voltage of the cell Vt.
This effect is measured to determine the state of the cell.
2.4- SLC Flash stores _ one bit value per cell _, which basically is a voltage level. The bit value is interpreted as a “0” or a “1”.
Since there are only two states, it represents only one bit value, each bit can have a value of “programmed” or “erased.”
For more data, you can send the question to the Support Team : Link: http://kb.sandisk.com/app/ask/
Regards, Alfred. (Google translated)