Breaking News
Comments
Newest First | Oldest First | Threaded View
chipmonk0
User Rank
CEO
Re: Memory stacks
chipmonk0   2/11/2014 3:26:57 PM
NO RATINGS
Everyone seems to be backing off from putting a stack of memory chips directly on top of a processor ( per the original JEDEC wide I/O spec ) because of yield, logistics, KGD, thermal -- whatever.

But at least by stacking DRAM chips w/ TSVs they are shrinking the distance btwn individual chips on DIMMs and just about eliminating sync-ing / latency due to chip to chip propagation delay.

both Micron HMC and now HBM ( its a JEDEC std. not just SK Hynix ) put the memory stack off the processor but on the same PCB, or substrate / interposer be it organic / Si. So the resut is either 2-d or 2.5-d with the memory in 3-d, not a pure 3-d

Micron's HMC memory chip stack includes a controller logic chip - all vertically connected by Thru Si Vias (TSVs). The stack sits off the CPU and is connected to it by SerDes.

At least right now, its aimed at the high end, FPGAs, Network Controllers that sort of thing

A certain mass market GPU vendor did n't like this configuration ( not willing to pay for the controller chip )

SK Hynix must have heard that complaint.

So their HBM is just a stack of memory ( w/ the controller chip optional ) all hooked up by TSVs, sits off the CPU / GPU, connected to it by parallel I/O with regular drivers ( as it stands now ) with the bandwidth 20 % slower at 128 GBps.

 

krisi
User Rank
CEO
0.064mm2 sram cell
krisi   11/5/2013 4:18:18 PM
NO RATINGS
Amazing small cell size...looks like Moore's law still holds

rick merritt
User Rank
Author
Memory stacks
rick merritt   11/5/2013 2:02:22 PM
NO RATINGS
I am hungry to hear what folks are doing with Micron and SK Hynix memory cubes/stacks. How is this different from 2.5-D stacks with a processor and memory on an interposer? What are the trade offs?



EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Glen Chenier

Engineers Solve Analog/Digital Problem, Invent Creative Expletives
Glen Chenier
1 Comment
An analog engineer and a digital engineer join forces, use their respective skills, and pull a few bunnies out of a hat to troubleshoot a system with which they are completely unfamiliar. ...

Max Maxfield

What's the Best Traveling Toolkit?
Max Maxfield
13 comments
A few years ago at a family Christmas party, I won a pocket knife as part of a "Dirty Santa" game. This little scamp was a Buck 730 X-Tract. In addition to an incredibly strong and sharp ...

Rishabh N. Mahajani, High School Senior and Future Engineer

Future Engineers: Don’t 'Trip Up' on Your College Road Trip
Rishabh N. Mahajani, High School Senior and Future Engineer
10 comments
A future engineer shares his impressions of a recent tour of top schools and offers advice on making the most of the time-honored tradition of the college road trip.

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
41 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...

Top Comments of the Week
Flash Poll
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)