What is RAM IC ? how does it work on mobile phones handsets

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.