FLASH IC AND RAM IC

There are two types of flash memory, NOR and NAND. The names refer to the type of logic gate used in each memory cell. (Logic gates are a fundamental building block of digital circuits). NOR flash memory was first introduced by Intel in 1988. NAND flash was introduced by Toshiba in 1989
The two chips work differently. NOR flash is faster, but it's also more expensive and takes longer to erase and write new data. NOR is most often used in mobile phones. NAND has significantly higher storage capacity than NOR. It has found a market in devices to which large files are frequently uploaded and replaced. MP3 players, digital cameras and USB drives use NAND flash.

NAND Flash is a special form of Flash memory. Flash memory is a memory technology that keeps data even when the power supply is cut off; this is known as a non-volatile memory type. Flash memory can be read pretty fast, but writing to Flash memory is pretty slow compared to many other -volatile- memory technologies such as SRAM or DRAM. Flash also has a limited number of write-cycles; manufacturers typically specify something in the area of 10,000 writes for the lifetime of the part.
NAND Flash is faster than regular Flash, although the general characteristics still hold.
Flash memory is widely used in digital cameras, portable MP3 players, USB (Flash) sticks, and many other devices.

NOR flash memory is a type of non-volatile storage technology that does not require power to retain data.
NAND devices are accessed serially, using the same eight pins to transmit control, addressing and data. NOR flash memory supports one-byte random access, which allows machine instructions to be retrieved and run directly from the chip, in the same way that a traditional computer will retrieve instructions directly from main memory. NOR flash has an SRAM interface that includes enough address pins to map the entire chip, enabling for access to every byte stored within it.

Some devices use both NAND and NOR. A pocket PC, for instance, may use embedded NOR to boot up the operating system and a removable NAND card for all its other memory or storage requirements.

Random access memory (RAM) is used in mobile phones circuit to store memory datas. It is made of millions of transistors and capacitors that being packed into integrated circuit (IC)
Transistors and capacitors are paired to create a memory cell, which represent a single bit of data. The capacitor holds the bit data of information, a 0 or a 1. The transistor acts as a switch that lets the controlcircuitry on the memory chip read the capacitor or cahnge its state. In most cases common form of mobile phones memory is a Dynamic random access memory (DRAM)
The opposite of RAM is Serial Dynamic Random access memory (SAM). SAM stores data
as a series of memory cell that can only be access sequentially. If the data is not in the current location each memory cell is check until the needed data is found.

SDRAM
SDRAM stands for Synchronous Dynamic Random Access Memory. DDR is short for "DDR SDRAM" and stands for Double Data Rate. Nowadays to avoid misunderstandings SDRAM is often specified as SDR SDRAM and SDR stands for Single Data Rate by analogy with DDR. Therefore, the main difference between SDR and DDR memory the doubled speed: DDR can transfer data at roughly twice the speed of SDRAM. 

DRAM. Dynamic Random Access Memory is used to temporarily store information on mobile phones. DRAM is made up of many cells and each cell is referred to as a bit. A cell contains a capacitor and a transistor. Since computer machine language is made up of 1s and 0s, it has the value of one when active and zero when inactive.
SDRAM or Synchronous Random Access Memory is the result of DRAM evolution. This type of memory synchronizes the input and output signals with the system board. Its speed ratings are in MHz. SDRAM was introduced in 1996 and is still used today. SDRAM transmits every clock count at a specific time.
DDR RAM (or Double Data Rate Random Access Memory) does the same but it does so twice every clock count. This makes DDR RAM twice as fast as SDRAM.