+1. I watched my course on Udemy at 2x speed, awesome. Initially it's unusal, but after a few hours of watching coming back to 1x speed was like sooo slooow :D
At 7.40 you are saying "At this point, these edges will start travel together". If they really do travel together at this point, then the positive edge below will arrive later because there is another "bump" in the trace. Isn't it ? I'm beginner to hardware design so don't hesitate to explain :-)
they have to arrive at the same time at the end of the track. the other track finish sooner, the 2nd wave is added so the lenght is the same on both track and therefore the wave arrive at the same time at the end of each respective track.
Hello, Robert Feranec! This is great video, i learned many things from it. And i have a small question, please explain for me. At time 7:01, i understood that the plus signal is further than minus signal, so the plus's edge will be ahead of minus edge. But, the end of the plus signal is further than minus, too. So, i think they will go to the end in the same time and in the case 2 layers is same electrical characteristics, do i think right? And if the 2 layers is differences in electrical characteristics, i think your explain is right "same length on each of layers" Thank you, Tuan
Hi Mr. Robert, I am eagle cad guy and switching to Altium. I saw your almost all video, your way of explanation is very very nice and directly understood. Can i expect video on Rigid Flex PCB design from start to end with example?? Thanks
I have doubt about impedence controlled routing. Is impedence controlled routing is controlling the track impedance within the limit (minimum value can be any) or maintain strict impedance like 100 ohms? Another one, impedance controlled routing can be achieved by using layer stackup or anything else.
A differential pair tracking was chosen to provide a signal a tolerance to any external influence. And at the same time a pair affects environment in a minimal way. Everything is because of opposite directions of signals in the pair, and routing them together. So is it really so critical to keep it far from other tracks?
Haz pensado actualizar a una segunda version este curso de " Advanced PCB Layout Course " a una version mas actualizada de Altium Designer ? Saludos, buen trabajo !
Thank you for this awesome tutorial. It's really helpful but we cannot find the answer to this: we need to twist a LVDS pair perpendıcularly (in an x shape) using vias between two layers that are separated by a thickness of 1mm. Would it be possible to do such a thing without causing crosstalk? Thanks in advance.
did you use the signal integrity simulations while you design your PCB ? OR JUST YOU FOLLOW ONLY THESES RULEs ? how much important the signal integrity simulation in high speed PCB design ?
I mostly follow the rules. I only simulate if I have to break important rules (e.g. if i have to route memory tracks too close to each other) or if I break too many rules.
Hi Robert,Fantastic advice, keep up the great work. Just a quick question on Diff Pairs. I see in some cases it changes layers. I feel its always best to not change layers and have a GND Plane above and below the diff pairs and this way, there is no problems with other singles crossing in any direction. As the diff pairs get there return on the GND Plane. Thank you again, superb work.
Hello Robert, I know total length (Source to destination pin) is matched. But are your matching the length layerwise too? I mean segment of D0 to D7 on layer 3 is also matched, or it is not necessary?Second question - Have you routed DATABYTE 1 group on same layer only? I mean (D0 to D7 in any one layer only, no spitting of bytes in different layer like D0, D1 D2 on Layer3; D4 and D5 on Layer8; D6 & D7 on bottom layer likewise?Your answer will be most helpful for me. Thanks.
Watch this my video reviewing DDR4 layout of a server board - it can help to answer your questions (espcially notice the part about propagation delay difference between layers): ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-rdlEm2xjCsc.html
Hai Robert. I regularly following your videos. I learned so many things and i have one doubt in ALTIUM for high speed design. How to set the constraints for pin pair in altium .Recently i designed DDR4 board. In that board i followed fly topology( daisy chain). In that design i will used 4 ddr's and i have to match the address signals length from one device to another device. But it is showing overall 4 devices length. How to know the each device length?Please let me know how to set constraint for that?
Thank you Gudimetla. Difference is environment around the tracks - signals travels different speed in different environment (in different materials). In top and bottom, there is air, inside of PCB there is resin around the tracks. That is what makes difference.
@@RobertFeranec Thank you soo much for answer. Another small doubt, will signals travel faster orr slower inside PCB's relative to top? Because then I can know which track to length match..!!
@@gudimetlakowshik3617 I would recommend you to watch this my video - there is a document showing that info: Review of Server PCB Layout & Schematic - Part 6: DDR4 Memory Layout & CPU Power ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-rdlEm2xjCsc.html PS: some software supports length matching based on delay, maybe that is something what you would like to use?
@@RobertFeranec Thank you for reply. I have recently came across in a linkedin post about a weird news. Donno whether it's true or not but the post said, "if you are using high speed designs try making your PCB RED in color because signals travel faster on red pcb's than any other colors." ....The post itself told that they donot know the reason for it. How much of truth is there in this statement? Is it correct or fake? Sorry if it sounds stupid but I just wanna ask this really bad...haha...thanks in advance....!!
@@gudimetlakowshik3617 I have never heard anything like that - we use a color which we like or we feel is nice for the product / pcb. Even if there was difference, I do not think it would be important for standards boards up to 5GHz. But, it would be interesting to see that article, why they are saying this and how they come up with this idea.
Can you confirm that in conclusion all this is obsolet in newer Versions with LayerStack activated Impedance Calculator (Rule --> overwrite with "use Impedance Profile 'Diff90' " ? But explanation in generall is brilliant simple. Thanks for that!
@@RobertFeranec Seems to be very difficult to get them from the cheeper ones. (wanted to try if it is possible to do some based on 2 Layers with lot of space)
Its a very Nice tutorial! But I couldn't find the next lessons (Lessoons 5/6) in RU-vid. Why don't you add them as well to your channel? Its a great effort! Thanks.
Hi Abin. The next lessons are not on youtube. You are asking, why. It may not look like that, but it took us 1 year to develop the boards used in the videos and it took me over 3 months to record the videos - full time - from morning to evening. And ... we are working on new things ... unfortunately for all this, we need money and that is why we can not place the videos on RU-vid - because we would not be able to do videos like this. I am sure you understand.
I shared some of our stackups in this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6aX9lA3W00A.html I do not remember the exact stackup, maybe it was this one? www.fedevel.com/welldoneblog/wp-content/uploads/2015/04/PCB-Stackup-Example-03-12-Layers.pdf
What is the maximum frequency that these rules can be used for a good quality design? I mean if we go to GHz signals are these rules still sufficient or do we need to apply more rules?
+Pejvaak Salimi We have designed number of CPU boards following these rules (PCIE & SATA were probably the fastest interfaces). For higher frequencies you may want to have a look at additional recommendations (e.g. adjusting impedance under component pads, VIA impedance, VIA length & stubs, ....)
Hi Robert, My question is Related to RF issues, how I can insert a PCB antenna on the footprint file? Do I have to design it from scratch or there is a faster way (Like on the shelf ) that I can use?
At 24:40 , "resistor should be put close to the output". If data is bidirectional, for example from usb controller to an FPGA, where should put the resistors?
Very often these series resistors are placed closer to CPU / FPGA on bidirectional data signals. However, I would maybe also consider the strength of pins (or possibility if you can control speed of rising / falling edge in registers) - in that case you may want to place the resistors on the side where you can not control rising / falling edge or on the side with faster rising / falling edge.
Thanks for your fast response. The videos have been very helpful for my first layout. Is it more important to match length or retain consistent impedance for HDMI signals when I'm limited with space or should you always be able to do both?
Lots of helpful insights. Thanks a lot for posting this video! Can you tell me about calculation of the required track width and spacing to have a given differential pair impedance? Is this information obtained from PCB manufacturer or do you have to calculate it yourself using those expensive field solver software? My experience is that not all PCB houses can provide this information even if they advertise that they make impedance controlled PCBs. And if you do your own calculations, they may still contain some uncertainty and you'll have to order test PCBs to verify your calculations at your own cost.
I always leave the final "track geometry" decision on PCB manufacturer and then I adjust my PCB to meet the requirements. For preliminary calculation I use mostly Saturn PCB toolkit as it's free and has also other calculators (e.g. maximum current through track or via): saturnpcb.com/pcb_toolkit.htm
Robert Feranec Thank you very much. I'll check out this software. I have a question about your online course "Advanced PCB design". You say you provide a certificate. Is there some kind of exam at the end of the course to qualify for the certificate?
bormisha There is no exam, but if you would like to get the certificate, you need to do some work. Each Lesson has some activities to practise. Only the people who work on the activities get the certificate.
Robert Feranec Thanks. Do I have to use the Altium Designer which is expensive or is it possible to complete your course with a different PCB layout software such as Eagle?
bormisha If you would like to get the certificate, you will probably need Altium as all the files are in Altium. If you would like to learn the knowledge, you can watch the videos and use a different CAD system. In this case you will need to find your own way to do certain things in your CAD e.g. differential pair routing.
This is the only lesson on RU-vid. If you would like to see more lessons, have a look at our website (it's a paid course): www.fedevel.com/academy/online-advanced-pcb-layout-course/
At 14.03 u ttell that the length of the serpentine should be lesser than 3W, i have a doubt about it in nexperia high speed routing guidelines they say it should be atleast 3W or greater . Please reply about this.
