Committed to Memory

Archive for the 'Signal Integrity' Category

 

Do you need DDR4 Write CRC?

A customer asked us, “Do I need DDR4 write CRC beyond a certain frequency?”

The answer is far from simple; it’s dependent on many factors including the type of system it is, the other types of error correction (ECC) that may be in use, the system’s tolerance of errors, and the system’s ability to spare the bandwidth required for the write CRC function. Since I’ve been asked a few times and since the answer is so complex, I created the flowchart here to show some paths through the possible choices.

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Posted in DDR Controller, DDR4, DRAM Industry, Featured, Signal Integrity, Uncategorized

 

Row Hammering: What it is, and how hackers could use it to gain access to your system

I have written on the topic of Row Hammering in a White Paper I published last year (link here) but since it is in the spotlight recently I thought I’d dedicate a blog entry to it. I had never considered this to be a security hole until this morning.

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Posted in DDR3, DDR4, DIMM, DRAM Industry, Signal Integrity, Uncategorized

 

The Future of DRAM

A lot has been written about DDR SDRAMs, both the compute variety (DDR3/4) and the mobile variety (LPDDR3/4) and what may come after these technologies run their course.  One thing is certain; the future will not be an easy path for DRAMs.  The DDR protocol based on a wide parallel bus with single ended signaling and a source synchronous data strobe and non-embedded clock is not scalable beyond the data rates currently specified for these technologies.  After DDR4, the world will need something else as the DDR interface cannot realistically be expected to run at data rates higher than 3200Mbps in a traditional computer main memory environment.  Unfortunately, that something else will likely be “somethings” else.  Likewise, the smartphone’s insatiable need for higher bandwidth from main memory DRAM will also lead to a deviation from the wide parallel bus based DRAM.

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Posted in DDR3, DDR4, DRAM Industry, HBM, High Bandwidth Memory, HMC, Hybrid Memory Cube, IP, LPDDR3, LPDDR4, Signal Integrity, Wide I/O, Wide I/O2