Memory SRAM and DRAM

Basic Types of Memory: SRAM and DRAM

Memory can easily be classified into two major categories, Static RAM, and Dynamic RAM. Like I said above, Static RAM uses a special arrangement of transistors to make a flip-flop, a type of memory cell. One memory cell can store 1-bit of data. Most modern SRAM cells are made of six CMOS transistors, and are the fastest type of memory on planet Earth.

In contrast, Dynamic RAM lines up one transistor with a capacitor to create an ultra compact memory cell. On the flip side, the capacitor needs to be refreshed after a specific period to keep the charge in the capacitor, which introduces a latency in memory access. Something we refer to as memory timings.

While DRAM has an obvious size advantage over SRAM, its speed can’t even get close to those offered by static memory cells (because they don’t need to be refreshed and are always available). That’s why faster memory is always made out of SRAM cells – like Registers in the CPU and Caches used in numerous devices. But thanks to much higher space requirements, SRAM is expensive and can’t be used as primary memory.

Read more: http://wccftech.com/history-ram-trip-memory-lane/#ixzz3huCTZHnk