Signal Integrity for High Speed Design

you test test hi good morning everyone since for joining our webinar this morning and so today we are going to talk about you know integrity for high speed designs and first let’s start of introducing ourself so we are security engineering we are similar simulation provider for the San Francisco Bay Area we helped many customers to speed up development identify reliability issues and optimize performance we also support full answers portfolio of tools so now we are going to go over the agenda for today so first we are going to diagnosing SI problems and what is the what is you know integrity and then we are going to talk about s-parameter crosstalk which includes flying cross top knee and cross talk and ground pound noise we also are going to talk about the summary of the result as I wave capability and conclusions so next we are going to turn noticing SI problems so first we want to know what it looks like so when you have si problem is usually when your circuit doesn’t work or when you send an input but receive an elusive in incurring a query output or when your circuit fails intermittently when when you do not have as like simulation tools you will not know what happens during the design process in this case you have to do it the hard way which you have to manufacture your design and test it physically this will consume a cynical significant of time and material investments sometimes even during the testing process you cannot find out where the problem is so today we are going to teach you the easy way using simulation tool as I wave is a dedicate tool for electrical analysis of full PCB and compare electronic package with s I believe you are able to test your design and try for the signal integrity issue before you manufacture it and make sure it works this can save you time and money for effective productions especially in modern day when PCB designs are require to have faster speeds in no smaller device there will in this case there will be more SI problems increase so next what is signal integrity so you know integrity usually adjust to issues coming and signal quality so timing means does the signal arrive at the destination when it’s supposed to be or and signal quality means is the signal in good condition when it arrives so a high frequency design usually there will be a lot of negative effects such as ringing crosstalk refreshments and guac power ground noise so this opposite effect can impact your signal and cause arrows and system failure so what this problems Costa Guapo noise usually caused by see no interference ringing refreshing are usually coves by impedance mismatch so here I have a picture shows you the eye diagram to solve you when you have ideal supply power surprise when you have a voltage regulator module or when you have a aggressor in light low frequency like let’s say 1.6 gigahertz and there’s a higher frequency at 4 gigahertz so as you can see goat goes down the row the there are more noise and more more noise so I’m also going to so this is our demonstration port today that I’m going to soju for today’s testing so let’s first go ahead and launch as I wave

so for si wave you can import many different file types from many design tools and SS and SS can cover most of the design tool file types so you can do ot be prosperous the SF and many setter so let’s launch so we have the design source here and first um for si wave here you can verify your stack up so here is for a different layer you can modify the thickness material conductivity etcetera so you can modify all your layers here and also there are many like pass tag these are two discs these are refers to via or any similar stuffs and we all our circuit elements are inductors capacitors register everything is included here so you came or you can assess it on in the Home tab everything is very easy to see so first thing we are going to talk about is s parameter as many these are engineer’s know like in circuit design we usually want to look at s11 insertion loss and s21 which is the return loss so let’s go ahead and so first thing you need to do in SI wave to run a syz parameter is to create our ports you need to set our reports before you run the simulation so here I set out a port for the MD k12 mdq 13 between 2 device so let’s go back here you can see a controller or a ram and a voltage regulator module so the controller answer I go driver and the theorem is a receiver so it comes back here you have the driver here so we have the port setup if your indica 12 Ambika dating driver and receiver and let’s go ahead and compute sy is the parameter here you can set your stop frequency stop frequency you can set the step size or number of point you want to simulate it and you can just simply launch and at the symptom um if you want to see all your nets you can assess your net everything is here so you have single net differential nets and is 10 the nets and here’s all your components and the squid device so we have the result here first you can assess your result here or you can go to the result tab and your result of sauce here so let’s go here we can just simply double click it so here you can so self Thames which is s11 and you can also see your transmission terms which is as to one that is at the same time you can also put your pro your s11 into the electronic desktop for comparison purpose let’s do it okay so we have so many here okay let’s put another one I probably just do one at this time you’ve got her plot yes or till it all of this here right now you can see if you click on this one you only have one pro-nuclear on this one

you have another proc but if you pull it over you can just drag and drop then you have to plot and you can see the conversion in this case maybe I have the same so let me put other one so you can see your different smoke clearly so checking job see now you can see the difference okay so the next thing we want to talk about is crosswalk so usually two atomic time domain crossed out here but we can also do a frequency domain crosstalk so if we go to crosstalk you can just do a tandem and crystal we also want to do it between the mdq 12 and DQ’d 13 so we just want empty q2 + DQ 13 next and here you can you have your reference design which is a driver receiver and we and you can set up your driver rights time and you can set up your driver voltage and input impedance so we just everything as default lunch solution is done so you can see the peak voltage here so this is in the case like here this cylinders here indicates a crosswalk between and acute curve and vicki lurking here is the same or if let’s say if you want to see more nets we can go ahead and input more yes so as you can see under the simulation tab you have many type of simulation you can do like PC R R which is the power integrity you can do resonant modes and you can do frequency sweeps for you near few and many other cells so let’s look at the crosstalk right now you can see all this crosstalk between light from m DQ 9 – m DQ 15 nets so here let’s click on one right now the one i’m clicking is m DQ 12 and m DQ 13 okay so here you can choose either you want to see far end or near and crosstalk so if you’ve seen here and this is your near and if you click on find this it will be a far end if you scroll down so if you want to see a product you need to click on one cylinder stay associate prot so right now we have the far and near end this space here or if you want to see V in V out so this is the V in and V out so let us see the more clear on the features here right now we have the crosstalk and we see consider here’s a V in and V house so usually when you see the near-end crosstalk this one is an earring croissant near in Costa is is related to the input voltage so the term of the rising time for the V in is the term that the cross happens so as you can see the width of the term rise is the same as as the cross thought that happens okay next we are going to talk about the eye diagram so here is a simply picture so do you are all those fetters in the tak diagram so in the eye diagram we have jitters Tammy jitters that’s the timing errors that results from misalignment of rise time and for stunt and with those definitely the smallest rope is better that means less humming arrow and which we also have the signal-to-noise ratio assembly points so that’s the ratio between signal power and noise power but higher ratio is always the better and we also have the distortion this is related to the SNR so the signal-to-noise ratio also if the amount of signal does be beyond the distortion that’s the wasted power for the eye diagram so next we are going to

talk about firing crostini and construct for the eye diagram so firing crosstalk is covering between two or more chests many pairs as the signal propagates in the same direction of from the chessmen from the driver to the receivers and in this case as you can see in this eye diagram here this is just the victim line itself so there’s only one chase between drugs and receiver and in this picture you can see there are two traces so one victim line and one aggressor so as you can see the noise here appears more than the picture one so which means there’s crosstalk between them and so if you can if you can see oh when the so when does it know sending from the driver to the receiver the rising edge will the right the rising edge will cause a voltage cause of voltage interference so you can see there’s a bulging there because windows you know is sending at the right time the signal the aggressor analyze keep progressing on the Vita mine at the same points so you can see the bulging here and so always faster rise time creates more crosstalk and so and foreign cost increased jitter and I closure and in this picture shows you like the rise time of the input voltage the input voltage is a when the cross what happens and we in this picture you can see more clear so there’s a when you have seen just a bit align yourself and there’s a question I and you can see there so belching here so when we have so the nest is a near and crosstalk so near and crosstalk measures the signal couple also measures as you know covering between two chip two nets so instead of firing crosstalk the signal propagating in the same direction near and Cousteau is computing the is measure the cluster of two signal propagate in opposite directions so in the in this feature you can very easy to see so this is a personal let’s say there’s you know propagating this way and if for the victim life you know probably in this way we gotta find Cosmo if we opt Gobert the signal will go back in a second with the other ways then it’s an earring croissants and near and questa also also also give you jitters and eye closure and at the same thing faster rise time creates more cross talks and so let me show you the demo for the coastal let’s go for as a wave so in this picture here we have so let’s go to a simulation so for the eye diagram you need to use as a wizard this is use if you want to simulate mmm if you want to get your eye diagram so right now let me show you just a victim myself so right now if we just do mdq 13 so if we go next so here you can see you have a receiver driver you can input your IPS model so that and then you can setup your type excitation source you can manage your source here and you have your input and you have your bitrate and which is a frequency use you have your delay wrightstown for some internal impedance etcetera if you go next so here you can set up your supply your power supply so let’s see here so buffer no internal voltage means ideal surprise ideal ideal power surprise so it doesn’t give you nice and that is regulating module gives you noise so in this case we’re going to use voltage regulated module for now and this is a power net let’s go next this is the voltage regular module well

circuit diagram so you can define your circuit elements here yes you say your step size stop town we can just go ahead okay and you will launch in the electronic desktop automatically and if you want to do a diagram you don’t usually need to set up ports when you sled on that it will set up for itself automatically so here you can see the so here’s the circuit model for the this side so driver decides the receiver and here this involves to create a diagram and this symbols is connect together – mm to defy the circuit between these two device and you also have this one is the voltage regular module circuit and right now the simulation is done if we go to result create a diagram so you can see there’s a 4 m DQ 13 you can see TX and RX TX means the transmitting anguish is the driver and the RS is the receiving end which is the receiver so we are going to see both of them okay so when we see the receiving end that means the firing crosstalk when you see the transmitter and that’s the mirror and crosswalks so this Auto crosstalk you can see so what happened if oh this is just written myself there’s no aggression eye or anything don’t and if we go next let me show you if we have to when we have the aggressor line so you can just go ahead and aggressor I so ambigú probe is right next to MV q 13 just go ahead okay setup correctly max max okay yes what just one load it okay while this is running once you have forgotten soju is when you have the cross here so in this picture you can see the cross salt right now is around for the thought Ambika 12 mvq 13 is around like 0.01 to vote and that’s because there are two traces so close to each other let’s see why plane if we move it a little bit further apart so let’s move it right here and just go ahead delete this point just move it a little bit further apart we can just go and then less to another simulation for Tonto Macross talks sewing as I wave you can also move your chases around very very easily so when when let’s say when you have importer design and then you just want to make minor change you can always modify it in as I wave just simply checking job or you can use tools like LOM elements and everything or generic you can do anything one here so here we can let’s look at the crust again so we were looking and take your 12 MP q 13 so MV q 12 and big luther king at this moment we can see the peak voltage is dropped to 0.005 which is only half of the pitch before so the distance between chases are

matters for the crosswalks so let’s check if the other one is done yes so let’s go ahead so we can take you 13 so ts is transmitting and so let’s look at the fighting crossovers so as you can see there are piston more noise than the then without rhythm lines so here’s a bulging if we look at the knee and cross talks you can see it appears more noise as well so if we got that to here so if we look at the near-end crosstalk go fine cross off here here has less noise more noise pouching and for nearing cross talks so for near-end crosstalk since the signal is propagating in different direction they are the aggression line aggressing on the vitalife at different points so the noise will appear most spread out across the eye so here you can see the noises everywhere across in the eye compared to this one and here you can just see a little bit more noise at this point then the fine cross talks and next so i’m going to show you the power and compounds so for programmable power supply as like a written or aggressor so when is a victim is where the serial data like so that’s when the serial their highlights other aggressors so the best is imposed to the fight this is simultaneous switching noise so that’s when current flows from the so that’s when current flows wanna device to the system from the device well to the system ground through wire or less a package traces and so the border to the background so you can see here in case of fast switching of i/o pins these inter connecting elements can select inductor so due to variation of in current across inductors voltage drop occurs so now that’s when the device well has different potential than the system ground so you have a different voltage between these two growl so the ideal case when the device growl and the system grounds are equal the output signal should have the same voltage volume but when the when the their grounds are not equal so that’s when the compounds happens the upper voltage difference and so what happened so that’s a case of power supply as a victim so what happened when the parser price of aggressor so that’s Israeli so as we know power supply can have a lot of noise and those noise I’ll come from many different environment so let’s say the parm so like an amplifier so like any parser price generate low level noise so for example with thermal noise while switching mode power surprised generate noise from switching changes transistors when you’re near regulate so in this case when you are when you are switching transistor that will generate thermal noise so that can be one of the power supply noise and that’s going to affect your signal chance meeting between Nats and at the same time higher input frequency can also result in more cost ox so and power and ground bounce all also increase tutor and I cosy so in this picture here you can see one is the top line is with ideal power supply and the bottom one is with the voltage regulator module so it’s not that it’s not an ideal supply power supply so let me so if let me saw you in the

simulation so if we go ahead and do another simulation we just do the same thing next as I was mentioned you can choose your power supply here so buffer internal voltage or is the ideal power supply so less it’s like knickknacks so remember this picture this picture is with the voltage regulator module so what happened if we have just the ideal power surprised so why is running let me show you this so when you have the eye diagram you can input a mask the mass is used to indicate how open your eyes want to be so in different design different designer wants the eyes to open they have different have different goal of how the eyes how the eyes open so the MA you can si in 20 tests hope you can input a mask so the marks can measure if your eye is open wide enough or is not enough so in this in that case you can make you can text to see if that’s the result you want to be so when the eye opens enough that means you have the signal transmitted properly in your as you expected if not then you need to make some changes so in this segment in the picture here you can see there’s no voltage regulator circuit anymore and because you are using ideal voltage source it might take a while okay so let’s just go ahead and press I believe there so yeah so as you can so it might take a while you might so just give your idea in this picture you can see this one is without Oh with ideal voltage source I mean I do power supply and this is with our ideas power it’s with a real power surprise so you can see the different very clear between these two so let’s store those let’s do the summary of the results so when you oh yes so another thing I want to show you is so easy interesting we want to test all the Nats between two devices so let me just go ahead for this okay anyways let’s hold open another demo so let’s do the eye I’m just going to terminate is okay okay

so usually we want to just measure the other nuts that transmitting our chest first you know between two device so in this case if we want to see what other nads between these two device the driver and the receivers so here is MV q 8 to mdq 15 so here you can see all these nuts kinetic between two these two devices and if we just go ahead and run a simulation between all these nuts next and we leave everything as default since I already input Ibis model and power supply next okay so for this type of simulation area doesn’t take that long there’s another grasing of as I wave like let’s say I have a tool I have 7 Nats right now between these two devices in a tech lesson 10 minutes or around minute so that can save you a lot of time to do like if you just wanna simulation you can save your love time to find out what the problem is so you can see if depends on how many nights you have it generates all this driver circuit and receiver circuit hmm that’s weird okay okay so to save your tongue I can just show you the result directly so here when you have your chase is just kinetic like this think it gives you a closed eyes because your treasure is not placed properly or and when you arrange your trace into the proper space it gives your open eye and you can add a mask to measure see your eyes opening of that meets your what you aesthetic meet your expectation and so you have the closed eye you have the open eye that’s or happen by just doing those sim simple changes and so to conclude our topic today we have s11 as parameters we have insertion loss return loss you can party in the electronic desktop to see the differences and we have the tandem and cross stop so if you move those chases to the chases close to each other you have a more cost happens and if you just move the only way far apart you’ll reduce it by half or more and also we have all these other grants so as I mentioned at the beginning you have the ideal power surprise you have to using the voltage regulation module with no aggressors and you have the voltage not ideal surprise with aggressors and this is at one point six this is at one point six gigahertz and this is focus so you can see the noise increasing they very straightforward between these either so there are some other SOA capability we have the e we have the EMI skin scanner um that can quickly scan inter desire for lose of variation which can

which can cause EMI problems we also can do some power integrity serve so we can compute this error we can do capacity capacitor optimization we also can compute resonant modes that can highlight the potential problems dental problem areas of the PCB package also helps to indicate the impedance a particular frequency we can do impedance skin that can scan the nads impedance between devices or on your PCB design we can do TDR TDR wizard that’s the time domain with fashion we can also compute our LGC that you can extract your value of io GC of the design at certain frequency and we have many other capability so to conclude our topic today as the demand for high frequency circuit increase signal integrity problem will also increase so in order to save your term and to save your money on material investment simulation tool is definitely a great tool to have you to create effective productions and SSI wave can provide you were powerful and easy to use solution for electronic designers if you have further question feel free to conduct contact us so my name is different I’m the application engineer singularity engineering and below is my email and phone number and our website so feel free to contact me if you have any question and I will post this video on YouTube later so you can also comment under loop YouTube and thanks for joining the webinar today thank you