Alex Moltzau 莫战

Apr 19, 2020

4 min read
Ofelia Plads, Kvæsthusbroen, København, Danmark — photo by — @kaspercph

Ferroelectric RAM vs. MRAM

What oppositional advantages and disadvantages are there?

FeRAM is one of a growing number of alternative non-volatile random-access memory technologies that offer the same functionality as flash memory.

Ferroelectric RAM was proposed by MIT graduate student Dudley Allen Buck in his master’s thesis, Ferroelectrics for Digital Information Storage and Switching, published in 1952. The story of Dr. Dudley Allen Buck could be a cold war thriller. He was a code breaker and was working on the cryotron with the idea of switching between 1s and 0s — an idea that may have contributed at least partly to modern computing. He thought of using magnetic cores as well as and became a professor at MIT. Sadly he died at the young age of 32, some believed he was assassinated by KGB, although there is little proof to substantiate this claim.

The advantages of FeRam

FeRAM’s advantages over Flash include:

  • Lower power usage.
  • Faster write performance.
  • A much greater maximum read/write endurance
  • FeRAMs have data retention times of more than 10 years at +85 °C (up to many decades at lower temperatures).

The disadvantages

  • Much lower storage densities than flash devices, storage capacity limitations and higher cost.
  • Like DRAM, FeRAM’s read process is destructive, necessitating a write-after-read architecture.

One of the first commercial applications of FeRam was curiously enough in Playstation 2.

One of the manufacturers of this is Cypress Semiconductors.

Cypress F-RAM

A different company manufacturing MRAM would of course argue otherwise. This company is called Everspin.


Why Replace a Ferroelectric RAM with an MRAM?

Magnetoresistive RAM (MRAM)

Magnetoresistive RAM is inherently non-volatile, has unlimited endurance with no known wear-out mechanism and is not subject to data loss at higher temperature operating conditions.

Again according to Everspin this is why you should change to MRAM:

  • “Everspin MRAM is available in a functional equivalent or drop-in replacement for most FRAM devices.
  • Immediate (<1ns) Power-off with no loss of data.
  • Unlimited read and write cycle endurance.
  • Truly Asynchronous SRAM compatible speeds and cycle times.
  • 20-Year data retention with no cycling dependence.
  • No wear-out concerns.”

Is the wear-out concerns founded?

It would be interesting to talk to an expert.

This article was not comprehensive, however I am simply attempting to understand the subject to a larger extent.

Memory technologies can be relevant to most compute, however I consider it important in the context of artificial intelligence.

This is #500daysofAI and you are reading article 321. I am writing one new article about or related to artificial intelligence every day for 500 days. My focus for day 300–400 is about AI, hardware and the climate crisis.