Terminology » Components » NOR Flash Memory: Advantages and Disadvantages

NOR Flash Memory: Advantages and Disadvantages

flash memory memory nor nand embedded system

This page explores the advantages and disadvantages of NOR flash memory, providing a basic overview.

Introduction:

Embedded systems are becoming smaller and smarter, driven by the adoption of fast communication technologies like 4G LTE, 5G NR (New Radio), and GPON. These advanced systems demand high processing capacity, which is achievable using flash memory types such as NAND and NOR.

What is NOR Flash Memory?

The figure below illustrates the architecture of NOR flash memory. It consists of multiple source lines connected to a single bit line. As shown, word lines above each source line pass through the bit line. Each cell is connected to one bit line and one source line.

An example of NOR flash memory is the S70GL02GT series manufactured by Cypress Semiconductor Corporation (now part of Infineon Technologies AG).

NOR Flash Architecture

Image courtesy: Cypress Semiconductor Corporation (Now part of Infineon Technologies)

The typical average read speed of NOR flash memory is approximately 61.5 Mbps, while the average write speed is around 0.47 Mbps. The cell size of NOR flash is typically around 10F2.

Benefits or Advantages of NOR Flash Memory

The following are the benefits and advantages of using NOR flash memory:

  • Higher Read Capability: NOR flash supports faster read operations compared to NAND flash.
  • Ideal for Individual Read/Write: It’s often used in applications that require individual reading and writing of data bytes.
  • High Data Retention: NOR flash boasts a very high data retention capability compared to NAND flash memory.
  • Less Frequent Bad Blocks: NOR flash exhibits less frequent development of bad blocks than NAND flash.
  • Less Common Bit Flipping: It experiences fewer bit flips compared to NAND flash.

Drawbacks or Disadvantages of NOR Flash Memory

The following are the drawbacks and disadvantages of using NOR flash memory:

  • Higher Cost: NOR devices are generally more expensive than NAND.
  • Higher Power Consumption: NOR flash memory consumes more power compared to NAND flash.
  • Slower Write Speed: NOR flash has a slower write speed.
  • Lower Memory Capacity: NOR flash offers lower memory capacity compared to NAND.
  • Larger Size: NOR flash memory is larger in size compared to NAND flash.