Reference Designer

Here is a question and answer between DDR2 and DDR3

Question – Which one is faster DDR2 or DDR3 ?

Answer – Obviously DDR3 idiot. That is why it was designed for. A lot of money went into its design and implementation. Without any speed gain what would have been purpose of it.

Question – Thanks for clarifying it. So DDR3-800 is faster than DDr2-800 right.

Answer – No DDR3-800 is slower than DDR2-800. Actually higher speed grades of DDR3 is faster than DDR2-800

Question – But you said DDR3 is faster than DDR2 just now.

Answer – Yes I did, but DDR3 must be much faster in speed than DDR2 in order that the throughput difference will be visible. For example DDR3-1333 is faster than DDR2-800.

You can read more in DDR3 and DDR2 differences from Application point of view. .

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DDR3 improves upon the speed over DDR2. While DDR2 works upto a maximum JEDEC supported frequency of 800 MBps, DDR3 can work upto 1600 Mbps. The Speed increase, however, does not lead to the linear increase in the throughput owing to the increase in the cache latency.

DDR3 leads to several design challenges in maintaining the Integrity of the Signal on the PCB. Its operating voltage has been reduced from 1.8V to 1.5V leading to 17% reduction in the voltage and c lose to 25% reduction in the power consumption.

Its partial refresh feature which is used to refresh only the active part of the DRAM while in sleep mode further improves the battery performance.

From the topology point of view DDR3 utilizes dynamic on-die termination (ODT), ZQ calibration, and a fly-topology all designed to improve signal integrity. In the On die termination, the termination resistors are placed on the chip itself rather than that on the PCB outside the chip.  By Dynamic on die termination we mean that we can change the termination on the fly as required. The ZQ calibration command is used to calibrate the driver  impedance and the termination resistance value which takes care of the process variation due to temperature, voltage or the board discontinuity.

The topology of the  address and control lines in DDR3 chain from one DRAM to another, unlike DDR2 uses a T topology. This however, introduces skew between the signals.

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July 25, 2010

Today at 12:01, Eastern Time, ford is launching its much anticipated 2011 Explorer.  The 2011 Ford Explorer comes with many new features, like curve control, improved mileage and traction control.

Curve Control System incorporated into the new 2011 Ford Explorer is an advanced control system that is designed to prevent accidents in situations where the driver encounters a curve too fast, a situation that, according to Ford, could causes 50,000 accidents a year in the United States only.

The system is works from the technology “Smart Braking” developed by the Ford which is a device that can distribute power brakes to each wheel independently to prevent the loss of car control. And associated with this we have other elements that reduces torque and engine speed at about ten miles or 16 kilometers in just a second.

Operating systems associated with the balance of the car, both devices prevent skidding and loss of control of the Ford Explorer in the face of a curve too fast, keeping the car stable and reducing the risk of an accident.

Control System Curve oval house will be part of the standard equipment offered by the Ford Explorer 2011 and 2015 will be included in 90% of SUV’sy Ford Vans, later to be incorporated in all models manufacturer.

There is not much to know fully the 2011 Ford Explorer, which should be officially presented next July that almost begins

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I will try to explain the 301 redirection using an example. I had a a url as follows

http://www.referencedesigner.com/rfcal/cal_03.php

Obviously the url is not SEO friendly. I wanted to make it SEO friendly for the term vrms. The following url seemed to me a bit more SEO friendly

http://www.referencedesigner.com/rfcal/vrm-to-vpeak-conversion.php

I wanted to mention that at the time of writing, the search term vrms result in position 3 for this url. I am not sure if renaming the url and using the 301 redirect is going to improve the search ranking, but it is not bad to try.

So here is the change what I did in the file called

http://www.referencedesigner.com/rfcal/cal_03.php

I added the following code at the top of it.
<?
Header( “HTTP/1.1 301 Moved Permanently” );
Header( “Location: http://www.referencedesigner.com/rfcal/vrms-to-vpeak-conversion.php” );
?>

I let the code below it as it is, although I think it could be removed without any loss.  Then I copied the original  cal_03.php file to another file called vrms-to-vpeak-conversion.php. That is it. When I am searching for the vrms term the google search is still showing the
http://www.referencedesigner.com/rfcal/cal_03.php in its search result. I expect that to change to http://www.referencedesigner.com/rfcal/vrms-to-vpeak-conversion.php over period of time. I also expect to improve my search position. Am I expecting too much ?

seo

I just received this email in my in box. You may like to avail of this opportunity from world’s renowned signal integrity expert – Eric Bogatin.

Hi folks-

Cool off this summer with some of the new Signal Integrity Training programs at beTheSignal.com

Check out beTheSIgnal.comto see the details on these new events:

1. Our first ever Boot Camp on Differential Pair Design, scheduled for Monday Oct 4, 2010 in Santa Clara, CA. This is a 1-day intensive training program offered live and as an online version. Get all of your high speed differential pair design questions answered in this 1-day event.

1. Our most popular 2-day class, Essential Principles of Signal Integrity (EPSI) offered on Tues-Wed Oct 5-6, 2010 in Santa Clara, CA. This class will build a strong foundation for your engineering intuition by understanding the root cause of the most important SI problems.

1. Our 2-day Advanced Signal Integrity Design class (ASID), offered on Thurs-Fri Oct 7-8, 2010 in Santa Clara, CA, where you will learn to use analysis techniques to optimize the design-performance tradeoffs in your designs and have confidence your product will work before you release to fab.

1. Our first Professional Development Certificate program centered around our EPSI class. This online version of the Essential Principles class includes the recorded lectures of the live classes and additional lectures, readings and hands on labs. After completion and passing the quizzes and final, you will be awarded 4 CEUs and a certificate.

1. Four other Continuing Education Curriculum based on many of our more popular lectures and webinars.

1. If you are new to SI, you will want to try out our SI-101 continuing education program. It’s completely free to members, and, of course, membership is free!

Check out these new offerings!

Feel free to pass this note along to others you think might be interested in accelerating up the signal integrity learning curve.

–eric

*******************************************************
Dr. Eric Bogatin, Signal Integrity Evangelist
Bogatin Enterprises
Setting the Standard for Signal Integrity Training
No Myths Allowed Webinar Series
Public Classes
www.BeTheSignal.com
Blog: www.beTheSignal.com/blog
26235 W 110th Terr
Olathe, KS 66061
e: eric@BeTheSignal.com
v: 913-393-1305 cell: 913-424-4333 f: 913-393-0929
skype: eric.bogatin
***********************************************

Signal Integrity

It is great to learn that the 2011 Ford Explorer will have curve control. Every year there are more than 50,000 crashes from the sliding at the curves. The implementation of the curve control should help in avoiding these crashes.

Ford has the patent for the technology it uses. If the results are proven to reduce the crashes, it should probably be implemented in all the US vehicles.

The 2011 Ford Explorer is one of the best selling SUVs in US. The new curve control should be another reason for the buyers to go for it.

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