Parallel Termination Basics

Parallel Termination Basics - Phil's Lab

Рет қаралды 22,219

Күн бұрын

Basics of termination, reflections, and parallel termination for hardware and PCB design. Including practical considerations, simulations, and demos. PCBs by PCBWay www.pcbway.com
[SUPPORT]
Hardware design courses: phils-lab-shop.fedevel.education
Course content: www.phils-lab.net/courses
Free trial of Altium Designer: www.altium.com/yt/philslab
Free search engine for the best quality components from Octopart: octopart.com/
Learn about Altium 365, the electronics product design platform that unites PCB design, MCAD, data management, and teamwork: www.altium.com/altium-365
Patreon: / phils94
[GIT]
github.com/pms67
[SOCIAL]
Instagram: / philslabyt
[LINKS]
PCB EMI/SI: • Video
App Notes:
www.ti.com/lit/an/snla034b/sn...
www.sitime.com/support/resour...
www.analog.com/media/en/train...
[TIMESTAMPS]
00:00 Intro
00:55 Altium Designer
01:35 PCBWay
02:12 Termination Basics
05:42 Reflections
09:17 Parallel Termination
10:43 Practical Considerations
15:14 Simulation Demo
19:12 DDR3 Example
21:51 Outro

Пікірлер: 73

@xThirdOpsx 10 ай бұрын

Welcome back! Looking forward to this.

@PhilsLab 10 ай бұрын

Thanks a lot!

@TheStuartstardust 10 ай бұрын

@@PhilsLabyes! When is the series termination video coming out? Soon? 🤞 Great stuff! 💪

@user-hq9hf2ho3d 10 ай бұрын

Great Video Phil! I have your advanced hardware course where you also went over these topics and gave some more detail, but this video is also great.

@motion1776 10 ай бұрын

Something that could also be a very interesting Topic is high speed Signaling with connectors. Would be interesting to know how fast one can go with the typical 0.1 inch connectors

@PhilsLab 10 ай бұрын

Great idea, thank you!

@rick_er2481 10 ай бұрын

Great video, looking forward to the rest of this series!

@PhilsLab 10 ай бұрын

Thank you, Rick!

@user-ww2lc1yo9c 10 ай бұрын

@@PhilsLab Phil there is a mass confusion over the difference between bead, choke and inductor. They all have inductance but are not the same thing. I still do not understand the difference between these.

@lugaidster 10 ай бұрын

Thank you for this!!! Excellent as always!

@PhilsLab 9 ай бұрын

Thanks a lot for watching!

@fernwood 9 ай бұрын

Useful? It’s mind-blowing. I’ve been programming for over 40 years and had no idea, despite dabbling in electronics and having a Ham license. This gives me such an appreciation for the EE behind it all.

@pralhadjoshi7183 9 ай бұрын

Actually I have q . I am a beginner for the high speed design can I get to know what does programming 🤔 mean for pcb design.?

@gsuberland 10 ай бұрын

I've recently been working on LVCMOS18 termination for a friend's 50MHz Z80 backplane project where there can be up to 8 cards (with arbitrary order and 0-8 slots populated), with varying load capacitances, connector stubs, and a fairly long max distance (>200mm card to card in the worst case). Super tricky and had to spend a lot of time figuring out things like drive current and termination strategies by reading a ton of appnotes and the PCI spec, and doing days of LTRA simulations in LTspice, so I'm very glad to see you doing this series to help reduce the learning curve for anyone else who finds themselves trying to tackle a similar situation.

@PhilsLab 10 ай бұрын

Thanks! Sounds like an interesting project - hope all goes well with that! Currently doing a DDR4 design and also keeping my fingers crossed :)

@shabeesatsangi 10 ай бұрын

this one is the best and to the point with great practical example and solved my many queries. thanks alot.

@PhilsLab 10 ай бұрын

Thank you very much!

@leonardobortoluz8947 9 ай бұрын

Thanks Phil for this amazing video. Your explanations are a masterpiece.

@PhilsLab 9 ай бұрын

Thank you, Leonardo!

@youtubeviewer7077 6 ай бұрын

Big fan of your content. If you're open to suggestions; it would be great to have a series about making a real product with an FPGA such as Ice40 using only open source tools, all the way from part selection to schematic, PCB layout, and then programming/bring-up. Similar-ish to the Zynq series, but more hobbiest-oriented. The Zync videos are great but due to cost and complexity of the FPGA used are somewhat out of reach to amateurs/hobbiests such as myself.

@exciton007 10 ай бұрын

Thanks for the great video❤

@threewheeler7 10 ай бұрын

Wow, this is great!

@Graham_Wideman 10 ай бұрын

Phil: Highly informative video once again! It got me thinking that it might help the intuition if, along with the voltage waveforms (like at 18:07) comparing unterminated and terminated lines, we could also see the current waveforms in those lines. There I think termination trades some high frequency ringing current at the transitions for lower-frequency current at the fundamental frequency of the digital signal. Ie: Consider a 100MHz square wave signal: Unterminated there will be bursts of ringing current at the edges, but maybe not much at 100MHz. Whereas terminated the ringing is suppressed, but there are solid pulses of current into the terminator at 100MHz. (And that all leads to topics of track layout, return path and location of the bypass caps needed to handle driving that current, and also absorbing it at the terminator.) Anyhow, it would be reassuring to see these speculations confirmed or undermined by simulation or actual measurements!

@EhsanAlnazi 10 ай бұрын

Really, I like your videos and hope to continue.

@PhilsLab 10 ай бұрын

Thank you!

@bobodyuknow 10 ай бұрын

It would be very interesting to see how you can terminate for multiple high speed connector footprints. If you second source and put both placements on the PCb, can you attenuate reflections introduced by the trace stubs for the unplaced alternate 🤔

@techmakerandhacker7867 10 ай бұрын

please can you make a video about the lumped element thing you talked about . fantastic video btw learned a lot from your channel .

@joshuaplank883 10 ай бұрын

Thanks for the great video! I did have two hopefully simple questions. One was, could you expand on what it means when you say 'the driver is not strong enough to drive 50 ohms'? Also, why does the PCB house determine the line impedance? Isn't that something you can control with trace width/pour?

@lucas_liano 10 ай бұрын

As always, great video Phil! I was wondering if you know a good methodology to collaborate while creating a PCB project (from sch to layout). This is something that, i believe, would be very interesting for many people. Thank you again for your contribution to the community!

@PhilsLab 10 ай бұрын

Thank you! Great idea - this is something Altium 365 is aiming to help with, however, I'll try to make a more generic ECAD tool video.

@lucas_liano 10 ай бұрын

@@PhilsLab Thank you for taking me in consideration. I'll keep in touch!

@remontlive 10 ай бұрын

Very useful, thank you!

@PhilsLab 10 ай бұрын

Glad to hear that, thanks!

@Monpjc 10 ай бұрын

Hi Phil hope you are well and great video as always. I have questions: First when looking at trace length I assume we would not take into account the extra length to the termination resistors if after the last pin as per your example. Then I don’t know this one but would a cap with a Z matching the line Z and rising edge freq also work? 🤔

@kodizhuk 10 ай бұрын

thanks for the video

@PhilsLab 10 ай бұрын

Thanks for watching!

@bobodyuknow 10 ай бұрын

Also routing above 45 degrees begins to introduce further reflections. I am surprised the gigabit layout didn't use the bendy wendy routing it still looks like 45/90 degrees are used?

@rafalzasada8826 9 ай бұрын

Which termination is more important, parallel or series? I guess you can't use them both at once because you would reduce signal at receiver by half. Also, apart of the case e.g. for DDR memory where those resistor are part of the design, I guess it is difficult to select value of parallel resistor - if it is too high improvement will be small, if it is too small voltage at the receiver may go down to an unacceptable levels.

@THEELECTRICGUY 10 ай бұрын

Hello, Phil! Once you did a video about the Patch Antenna for ESP32 with Robert! Did it worked?? I didn't find any video of you testing it! I am also planning to test out similar thing in future.

@GregCoonrod 10 ай бұрын

I was just starting to do some research on bus termination. Perfect timing!. I want to get the most out of an ISA style bus in a retro PC design. Is there anything in particular that I should focus on for a 5V system bus?

@PhilsLab 10 ай бұрын

Awesome, glad to hear that! I'd check what others have done an ISA bus (I assume it won't require much in the way of termination), e.g. retrocomputing.stackexchange.com/questions/19880/how-do-i-terminate-an-isa-bus-correctly maker.pro/forums/threads/isa-bus-termination-question.113863/

@GermanMythbuster 10 ай бұрын

*I would love to see a High Power Function Generator Amplifier* ❤❤ Maybe use the ADA4870, I had an eye on it (at least as an amateur 😅) +/- 20V, 1A, 52Mhz+, 2500 V/µs, Low noise, short-circuit and thermal protection... Sounds all good to me 🤔 Professional ones are so gosh dang expensive. For example the Siglent SPA1010, 1Mhz 10W amp, costs 400$. Why I don't get it? 😥 *Would love to see your take on it* ❤❤

@suncrafterspielt9479 10 ай бұрын

Very nice video :D

@PhilsLab 10 ай бұрын

Thank you!

@87Spectr 10 ай бұрын

Thank you very much for video! Could you explain how to choose Termination Voltage?Does It depends on?

@PhilsLab 10 ай бұрын

Thanks for watching! Depends on a few factors: the specific bus/interface and its voltage(s), choosing Vt aiming to minimise avg. power consumption, etc. I'd recommend looking through the app notes in the description for detail.

@DavoidJohnson 10 ай бұрын

How good was that!!

@PhilsLab 10 ай бұрын

Thank you!

@km-electronics1 10 ай бұрын

Welcome back

@PhilsLab 10 ай бұрын

Thank you!

@avinadadmendez4019 10 ай бұрын

Hello, very interesting. What about chips with ODT? I had a design with LPDDR4X memory, and because of ODT, I didn't require termination

@PhilsLab 10 ай бұрын

Thanks! LPDDR4 is a special case, as that includes termination even for 'ACC' signals. 'Normal' DDR4 will require external termination for certain signal groups.

@avinadadmendez4019 10 ай бұрын

@@PhilsLab very great. LPDDR4 seemed too easy in general. It didn't even require length matching! The only proper care needed was to keep trace impedance and avoid crosstalk / via stubs I hope to have the chance to work on something more complicated later on

@RicoElectrico 10 ай бұрын

Yeah, as someone making MIPI IP I was surprised why anyone would not use termination on the chip itself. After all, on-die termination can be tuned or calibrated in case of issues.

@sanjikaneki6226 10 ай бұрын

can you set the logic family from the symbol itself? asking since setting this up for each board is not ideal. Also how you you enable simulation only on certain nets? asking since it was trying to use 12v and odd things s transmission lines? PS also how do you handle a transformer in this analysis ? as AC ?

@PhilsLab 10 ай бұрын

Yes, you can add SI information when you create the schematic symbol. You have to do some set-up before performing simulations (e.g. defining power nets, using planes instead of polygon pours, etc.). Everything is document on the Altium sites.

@7volatileint7 10 ай бұрын

is the corrected crosstalk video still in the works?

@PhilsLab 10 ай бұрын

Yes, waiting for the test boards to be manufactured!

@tolkienfan1972 10 ай бұрын

Does Altium have a license priced low enough for hobbyists? I couldn't find a license worthwhile for occasional use.

@BMM66666 10 ай бұрын

How to determine the termination resistors tie to some voltages or tie to ground?

@Graham_Wideman 10 ай бұрын

First, the particular termination voltage (VT) has no effect on the termination impedance, so you are free to choose a VT by other reasons. So the goal would be to pick VT to minimize average power dissipation. If the signal duty cycle is about 50% then VT at half of the signal amplitude would be good. But if the signal spends most of the time high, with brief low pulses, then making VT equal to the signal high voltage will save a lot of power. However, there's another thing to check, and that's the amount of "sag" due to the load of the resistor relative to the driver's current capability. As Phil shows at around 17:55, a termination resistor to ground will reduce the logic high voltage, while a resistor to VCC will raise the logic low voltage. Each of these reduces the noise margin for that level, or may even cause the signal to be unable to make it across the threshold of that level. So that has to be calculated based on the source and sink current capabilities of the drivers, and the high and low thresholds of the receivers. It's important to note that some logic families have asymmetrical output drive capabilities and/or unequal input logic level thresholds, so you have to consider all combinations. Hope that helps!

@deveshshevde-cp8xq 10 ай бұрын

sir what about that hades firmware we are eagerly waiting for that video

@marcorademan8433 10 ай бұрын

Hey Phil, surely the current cunsumption is off the charts here? But I suppose thats the price to pay for speed

@PhilsLab 10 ай бұрын

Hey Marco, Yeah, it's pretty hefty in comparison to other termination techniques, but also very effective.

@suncrafterspielt9479 10 ай бұрын

Would be interesting to see how bad the Overshoot/Undershoot of the ZettBrett is

@PhilsLab 10 ай бұрын

Waiting to get a new scope which I'll use to check out the DDR interface! So far no problem running the interface at max. bandwidth.

@suncrafterspielt9479 10 ай бұрын

very cool, cant wait for it.

@Graham_Wideman 10 ай бұрын

@@PhilsLab I'm going to be really intrigued to see what efforts are required to minimize the effect of the scope probes (or direct connection) on that type of signal.

@metl_play 10 ай бұрын

I every so often think of doing something with high speed, but KiCad isn't enough (I mean manually it's possible, but some tools would be good to have) and Altium Designer is way too complex.

@silvestrastancu1224 10 ай бұрын

Hi, that was a very good lesson. You don't want to do tutorials about DC-DC converters, car inverters or passive RC and LC filters.

@PhilsLab 10 ай бұрын

Thank you! I have some videos on RC filters, and DC/DC converters on my channel.

@bobodyuknow 10 ай бұрын

The problem with Altium SI tool is it is very buggy and hasn't been maintained or developed since 2018

@asmi06 10 ай бұрын

Unfortunately SI tools in Altium Designer are total crap compared to competition (for example it requires using plane layer type, which nobody uses nowadays, it doesn't allow selecting a set of traces to simulate as opposed to all, doesn't display locations of impedance discontinuities, etc.). Even much cheaper Cadence Orcad Pro has much more useful and functional tools for signal integrity.