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DDRx Memory Interfacing

Memory. Every system has it. Short-term, long-term, 2 nd level, static, dynamic, EPROM, graphic, internal, cache – but, by far, from an SI perspective the most common memory interface is DDRx. Double-Data Rate DDR memory arrived in the late 1990s, and has remained the dominant interface for decades. It has proven to be extensible and, now in its 5 th generation, DDRx has achieved a 20x increase in bandwidth. DDR memory occupies an important place in SI history. It was the force that drove ...

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Donald Telian, SiGuys - Guest Blogger 6/4/2019 Comments(0)

Measurement Correlation

I believe what simulators tell me. It’s funny because, throughout my career, I’ve met many who don’t. How is it that I somehow learned to trust them? Measurement Correlation. Over the years, taking the time to build, measure, and compare what I simulated taught me what’s good – and what’s not so good – about simulation. I developed confidence in my results and intuition that tells me when they’re suspect. Said another way, I learned to get value ou...

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Donald Telian, SiGuys - Guest Blogger 5/8/2019 Comments(0)

Simulating a Serial Link

And now one of my favorite topics: simulating a serial link. Good technology, good models, good margins, endless options. Yet how do I construct an accurate simulation? And what do I measure? Part of what makes this topic interesting is the variety of answers out there. And the almost infinite number of dials makes the task an engineer’s dream. In a world like that, how do I get started? …and how do I know when I’m done? How good is good enough? The Big Picture There are ...

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Donald Telian, SiGuys - Guest Blogger 4/15/2019 Comments(0)

Thinking About Power Integrity

Early February, over a foot of snow outside my office and the power is out. Good day to think about Power Integrity. Power matters. But why here in a series on Signal Integrity ? Good question. Power Integrity PI and Signal Integrity SI are intimately intertwined. Here are a few reasons why: PI and SI problems cause similar intermittent issues in systems PI problems can cause SI problems, and vice versa Because of 1 and 2 above, the problems are often solved by the same engineer Because of 1, 2,...

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Donald Telian, SiGuys - Guest Blogger 3/22/2019 Comments(0)

Understanding Trace Impedance

Author: Donald Telian , SI Guys - Guest Blogger The way high-speed signals interact with trace impedance has changed a bit over time, making the subject worthy of our attention. Thankfully, the importance - and even mechanics - of proper trace impedance is widely understood and agreed upon. So much so, the concept almost seems mundane – particularly against the rising importance of proper via impedance . However, I have found that engineers can benefit by improving their trace impedance in...

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Donald Telian, SiGuys - Guest Blogger 2/7/2019 Comments(0)

Managing PCB Crosstalk

Author: Donald Telian , SI Guys - Guest Blogger Crosstalk occurs when energy in one signal often called an aggressor couples onto another signal the victim adversely affecting the victim signal’s performance. The aggressor/victim language associated with crosstalk indicates danger is lurking, provoking a hardware engineer to consistent vigilance. How can we tame this foe? Or, more specifically, what causes crosstalk? …when does it become problematic? …and what can you do to ens...

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Donald Telian, SiGuys - Guest Blogger 1/16/2019 Comments(0)