RAM in detail (SDRAM’s) 1


We already know what is RAM. So in this post will learn more about in RAM in detail.
Nowadays we use DDR SDRAM’s. The thing common in every RAM is it has an Integrated Circuits (IC) on it. IC has a bunch of electronic circuits on a single small chip.

Now let’s talk about DDR RAM’s
DDR stands for Double Data Rate. The RAM that is in the market is DDR3 but before DDR3 were DDR2 and DDR/DDR1.

Let’s see the various DDR’s

1. DDR

  • DDR/DDR1 RAM started in around 1996.
  • It works on around 100-200MHz.
  • The IC is in the shape of large rectangles in DDR1 RAM.
  • The type of IC used here is TSOP which stands for Thin Small Outline Packages.
  • TSOP are very low profile i.e. around 1mm and the spacing between the lead is very-very low.
  • It has 184 pin configuration.
  • Voltage used 2.5
  • Price of 1GB DDR RAM= 1350Rs.

 

2. DDR2

  • After DDR1 came its successor DDR2.
  • It works on around 200-500MHz
  • In DDR2, the IC is in the shape of small squares.
  • The type of IC used here is BGS which stands for Ball Grid Away.
  • BGS is used for mounting the IC permanently on a surface.
    In BGA, you can use the bottom area and in TSOP, just the perimeter is used .
  • It has a 240 pin configuration.
  • Price of GB = 1145Rs
  • Voltage used 1.8V

The Main advantage or key point of DDR2 is :
Memory cells are configured in such a way that they clock at 1 quarter (in DDR it was half) of the bus. Thus, it operates twice the bus speed of DDR1.

 

ddr2

DDR RAM

 

3. DDR3

  • It works on around 400-1000MHz.
  • In DDR3, the IC is in the shape of small rectangles.
  • It has a 240 pin configuration same as DDR2.
  • Power consumption is very low, i.e around 25-30% less than DDR2.
  • DDR3 has increased Data transfer speed than other DDR’s.
  • Price of 2GB = 1500rs.
  • The voltage used 1.5V.

The Main advantage of DDR3 over DDR2 is :
Ability to transfer data at twice the rate of DDR2 (eight times the speed of its internal memory arrays), thus enabling higher bandwidth or peak data rates.

 

DDR3 RAM

Notch position In these SDRAMs :

  1. DDR1 almost in the middle just little towards the right half.
  2. DDR2 in the middle.
  3. DDR3 in left half side.

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