A 1T SRAM? Sounds Too Good to be True!

Zeno 1T SRAMAt the IEEE’s International Electron Device Meeting (IEDM) in December a start-up named Zeno Semiconductors introduced a 1-transistor (1T) SRAM.  Given that today’s SRAMs generally use between six and eight transistors per bit, this alternative promises to squeeze the same amount of SRAM into a space 1/6th to 1/8th the size of current SRAM designs, leading to significant cost savings.

The device is really a single standard NMOS transistor that behaves as if it were two bipolar transistors connected into something like a flip-flop, although the transistors’ bases are open, rather than cross-coupled to the opposite transistors’ collector, as is done in a standard flip-flop.

The cell is selected by activating the gate, and the bit is set or sensed via the source and drain to provide a differential signal.

This is a decidedly clever departure from standard SRAM configurations, and it reflects a careful observation of the actual Continue reading

Memory Issues in Space & Medical Applications

How an alpha particle disrupts a memory bitThe Memory Guy was recently asked about using memories in a satellite. What would be a good technology to use in a space application?

The problem with space is that there is a lot of radiation.  Radiation on the earth’s surface is lower because it is stopped by the atmosphere, but in space there is an abundance of radiation that interferes with most semiconductors.  Radiation is also a concern in certain medical applications where a memory must maintain its contents while undergoing sterilization through irradiation.  Experiments on conventional flash memories have shown data loss at only 2% of the Continue reading

Fundamentals of Memory – Free Online Course

Fundamentals of Memory Course - EE TimesSome time ago The Memory Guy was asked by Numonyx (later acquired by Micron) to put together an online course for EE Times on memory technologies, explaining how each one works and where it is used.

Although the course was very well received, I never posted a link to it on The Memory Guy blog.  This post is intended to correct that error.

The course runs 75 minutes and covers the basics of DRAM, non-volatile RAM, SRAM, NAND flash, NOR flash, mask ROM, and EEPROM.  It explains each technology’s advances in size, cost and performance, leading up to the development of Continue reading

IEEE Spectrum: Did Bad Memory Chips Down Russia’s Mars Probe?

Radiation SymbolThe IEEE Spectrum published an interesting article postulating that Russia’s recently-failed Mars probe may have suffered from bad memory chips.  According to the Spectrum article the Russian government’s Official Accident Investigation Results faulted SRAMs:

The report blames the loss of the probe on memory chips that became fatally damaged by cosmic rays.

Both the main computer and the backup computer seem to have failed at the same time, Continue reading

Cypress vs. GSI Battle Following Rambus Lead

RAM FightThe current battle between Cypress Semiconductor and GSI Technology caught The Memory Guy’s eye recently.  Many readers may have missed this battle that commenced when Cypress filed a Federal Trade Commission (FTC) lawsuit in the US in which the company asked for GSI SRAMs to be barred from importation into the US because of a patent dispute.

GSI has issued a countersuit with a complaint of anticompetitive practices.

What garnered my interest is how similar the tactics in this lawsuit are to those used for some of the Rambus lawsuits that evolved over the years: Continue reading


Jim Handy Objective Analysis Memory Market Research +1 (408) 356-2549 Jim.Handy (at)

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