How Retimers Built an $80B Company: The Story of Astera Labs

0:00In March 2024, a company almost nobody outside of the industry knew IPO'd at$36 a share. This June, it hit$499, joined the NASDAQ 100, and printed 93 % year-over-year growth at 76 % gross margins. Astera Labs doesn't even make GPUs. They don't make memory. They don't make optics. Astera makes the chips that fix copper, the little devices that catch a dying high-speed signal halfway down the board and relaunch it clean. Unglamorous, invisible, and in every single AI server, NVIDIA's partnership. Today's episode is the story of how a repair part became a franchise and how that franchise is now going after the biggest socket in the AI rack.

0:49Hello everyone, welcome to Semi-Doped. I'm Austin Lines of ChipStrat and with me is Vic Shaker of Vic's newsletter. So Vic, let's talk Estera Labs, but let's talk retimers. Like when I first heard about retimers, I was just like, what does that even do? What does that mean? So what do you say? Should we get into that today? Yeah, like let's talk about the problems of copper connectivity, which we have spoken about a lot before. But I think retimers is an interesting concept because we always talk about stuff that is outside, let's say a server tray, right? We talk about how GPUs are connected together in scale-up.

1:23We talk about how to connect racks together and scale-out and scale-across, all of that stuff. But what we've never covered is, how does a GPU connect to a CPU within a server tray, or how does a GPU connect to the network interface card, or the NIC? We'll keep referring to this as the NIC, N-I-C, network interface card. So how does that connection happen? you know it may not seem like it's much of a connectivity problem because come on how far are these things right like the server tray is maybe this you know a big with about two feet wide by four feet deep but that is still a problem because the way you connect a gpu to a cpu or to a nick is through the pcb that is inside the server rack right like it's it's a host board that is holding all these chips.

2:16And so those are not like excellent conducting mediums to carry high speed signals, right? And so that is the problem we're going to talk about today and how Astera Labs solved that problem and became pretty much an integral part of what is inside the server rack, a server tray today. Awesome. Interesting. Let's get into it. Yes, because already you got my wheels spinning because you're talking about copper PCB traces and high speed signals. And we've been talking about, like with Credo, you know, and active electrical cables, like the copper problem. So, yeah, let's get into it. When a GPU talks to a Nick and it talks over this, you know, PCB trace, like, what are we talking about?

3:00Okay, so let's go back from the beginning and like set the stage quickly, but also in a complete fashion so everybody understands what's happening in this part of the AI stack, right? fundamentally what happens outside you know we always talk about nv link for scale up or you know ethernet or you know infiniband all these things these are all like outside outside the server tray what happens inside is something that has been around like very long right this is in every pc that you build out it's been in gaming pcs forever it's called pci express or pcie okay So PCIe is how the GPU communicates with the CPU or the NIC, for example.

3:43It's just a protocol that's been around for a very long time. So the whole idea is that these don't have to run very fast on a single lane basis. However, they have many parallel lanes. So a PCIe interface can have 16 lanes, and so it's called a PCIe X16. Now, the way this is dealt with or spoken about is that you have so many gigatransfers per second, right? So you can have, let's say, a Gen 5 PCIe, you know, has essentially, let's say, 32 gigatransfers per second. This was actually used in the Hopper era anyway for connectivity. So what that means is that, why are we saying transfers and not like bits, right?

4:31We are talking about transfers because we are talking about transferring a symbol. A symbol can be a collection of bits. It can be one bit is one symbol, which is basically this NRZ modulation, zero or one, very simple. Or it could be a PAM4 modulation, which is like four levels, right? So you could have different kinds. Like, so when you do PAM4, you have two bits to a symbol. So gigatransfers means you're transferring 32 billion symbols of either one or two bits every second. So if you look at that in the time domain, like let's see, so what are we talking about? How many symbols every second?

5:11So every 31.25 picoseconds, you have a symbol going by. So you think of a string with like a lot of beads on it and each bead is a symbol and the beads are moving from left to right, right? So that's how it looks. if you kind of imagine bits moving on a wire. That's exactly what's happening between the GPU and the CPU. Did you say picoseconds, like 10 to the minus 12? Yes, yes, it's very less. It's a very small amount of time. And that's what it takes to transfer like a billion symbols per second. It takes picoseconds. It's a very, very small period of time. And so the thing is that it's not easy to do this.

5:54okay it's not easy to move bits across from one place to another because it faces several problems copper is a problematic medium and when you try to push these bits from one place to another things go bad okay so one thing is like loss right like you know you put you know a signal of high strength in one end and it loses all its strength by the time it reaches the other end of the wire right that's one problem then the pcb itself has problems and all that and then these things are like high speed signals so you you can think of them like sometimes they ping pong they reflect from that end so you can think of the beads trying to come back on the wire you don't want that right those are reflections right uh then crosstalk you know if you put two sets of beads uh next to each other imagine if one bead on this string is affecting the bead on the next string that's a that's a terrible outcome but these things happen in copper so all of these things they basically need correction they need some way to fix this right but that's just a copper thing actually i should mention that there are two more problems we should talk about and that is inter symbol interference is one of them which means the beads on a string don't actually stay like one bead on the string like imagine that you know they're made of sugar or something and they try to like stick to each other and try to become you know one larger ball of sugar instead of like staying distinct sugars.

7:17Like as they travel really fast, you can imagine they like eat up or something and then try to stick and become one and like a blob, right? That actually happens all the time. So when one symbol travels, the next symbol kind of starts to overlap with it and it starts to spread out and that's terrible, right? You don't want inter-symbol interference. The second thing that happens - Let me jump in there for listeners. So you can think of, if you're familiar with like square waves or sine waves like if you have a square wave you can imagine that as it travels down this medium it starts to spread out instead of being a square you know maybe it's like more of like a hill and so you can imagine if you're sending these different like pulses in the simplest sense that as they start to spread out they could start to overlap each other to the point of like the sugar sticking together so now the sun instead of like a a steep up to one steep down to zero some space and then another steep up to one you start to get like a ramp up to one and a ramp down and then maybe it overlaps another one to the to the point where what you receive is like a 0.5 and you're and it's slowly transitioning and it's a little bit confusing is this a one or is it a zero and then of course to your point as you mentioned earlier there's this attenuation so by the time it gets all the way down the copper it's just like lost, you know, the peak amplitude as well.

8:34So, but, but back to the inter symbol sort of overlap here. Yeah. There's like this smearing where you tried to send certain symbols and they're kind of overlapping each other. And somehow we have to figure out what was said at the end. Yep. Carry back on. What's the, yeah, yeah. What's the next one that you were going to mention? Yeah. The other one is jitter, which means that the pulse is not where you think it is, right? the pulse you think you sent it some time ago but by the time it reaches a given location it's it isn't there there are random variations in the system that cause the pulse to be further than you think it is or like earlier than you think it is so when you go in be like okay at this moment i'm going to look and see if this is a one or a zero and i'm going to like lock it down right like that's what you're saying like let's say that you know the 0.5 question isn't the thing like we are constantly monitoring this particular point on the wire.

9:30And we're going to be like, okay, when the thing comes, I'm going to call it a one or I'm going to call it a zero. But the thing doesn't come at all. Or it comes like, you know, late. And you're like, what happened? So now you can't detect the bit because the thing wasn't there when you expect it to be there. That thing is called jitter. And that also causes problems in communication. All of these are big issues. Gotcha. Okay. Yeah. So you're saying like with jitter, it's like, if I'm thinking about like, I'm on a clock, I'm at the end of the wire I'm checking and it's like what am I reading what am I reading what am I reading it but but nothing comes but then it comes to a tiny bit later like in between readings or something you know it's like what's going on here but let me ask you Vic between the inner symbol interference in the jitter like how much of that is deterministic like we can figure out oh this is copper and we know how a high frequency symbol behaves and how much of that is just like random noise or random something randomness?

10:26I think that intersymbol interference is somewhat deterministic and you can kind of figure it out and there is a way to do this and I'll get to that. Jitter is more random you really can't do much about it and all this affects how we will ultimately detect if it's a zero or a one. See that the whole problem here is to tell whether at any particular instant you have a zero or a one. If it's a two-level modulation, if it's a four-level modulation like PAM4, you have to tell which of the four levels it is. And typically, they talk about it in PAM4 as zero, one-third, two-third, and one. Instead of trying to use something else, they just break up the one into four levels, right?

11:17So it's up to you to tell what the level is. That's the whole problem. Yes. Okay. Yeah. I could see how that's challenging, especially for PAM4. Like if you're trying to read zero volts is zero, zero, a third volt is zero, one, two thirds volts is one, zero, and a volt is one, one or something like that. Yeah. How now all of a sudden when there's that smearing and stuff, it's not like, oh, is it a zero or one and we're at 0.5 and we don't know. Now it's like really crazy. It's like, oh, it's supposed to be 0 or 0.33, but I got 0.28 volts or 0.16 volts. You know, it's tighter. There's like less, there's less margin.

11:55Yeah, yeah. There is a nice way to visualize this. And you will see this mentioned a lot in this interconnect world. And those are what are called eye diagrams. Okay. And I'm just going to explain quickly what that is. So imagine that this one particular time called a unit interval, that is basically the 31 picoseconds that I mentioned. Because you know that that is the symbol period, right? That's the period. So that thing is called a unit interval and usually on these charts you'll see it as UI. And so you're looking in that unit interval and you're seeing all the bits that go by. Like you're looking at just one bead on the string, but that bead is moving, right?

12:33Like you're continuously looking at the string. Think of it that way. And what you're looking at is an overlapping bunch of zeros and ones, for example. And always you want to have some kind of a separation between zero and one, right? So that you can clearly say anything above 0.75 is a one or anything below 0.25 is a zero. Like we just round up that round down that way. And so, but nothing should be there between 0.75 and 0.25 because you don't know where it goes. The uncertainty is too much, right? Right. Yeah. So that that gap is usually referred to as the eye opening. The eye of the signal must be open because if the eye closes, which means there is no space between the voltage levels, you can't tell what it is.

13:19So the eye opening determines everything. OK, OK. So you you basically take a bunch of snapshots at this unit interval and then plot them all like on top of each other. Right. So you take like a thousand of them. And in the ideal sense, you would have like a like a rectangle. You have a bunch of ones and a bunch of zeros and that's it. But of course, it like takes time to get up to one and time to get back down. And so that's why you kind of end up getting this eye shape because it like ramps up and ramps back down and same. And but your point is when you throw thousands of these measurements on top of each other, there should be some sort of gap where it's very clear.

13:53Hey, there's nothing in here. So it's clearly a zero or one. But if they start to like if that gap closes, that's bad news because, hey, some of these measurements that we took are in the middle and we won't know what to call it. Exactly. So now the whole problem of why Astera Labs solved this problem is that they needed to find a way to keep this eye open when the communication is going between a GPU and a NIC or a GPU and a CPU. And the distance is in the range of like about 30 centimeters. It's not that much but it's still required because at the speeds that we're talking about because gen 5 is 32 giga transfers per second gen 6 64 giga you know transfers per second and it goes to pam 4 so that makes it harder because you're adding more levels and you're going faster so it really requires retiming and then in the future we will go to gen 7 which is at 128 giga transfers per second with PAM4.

14:53So Gen 6 is already in, I think, in the Blackwell era of chips. It's being used. So yeah, we'll get to all this. But so Astara Labs is basically, their job is to keep the eye open within a compute tray. That's their whole purpose with retimers. So what are retimers, right? Let's get to that portion because we need to talk about, okay, now we have inter-symbol interference and we have jitter whose main effect is to close the eye. Now we have to find a way to fix it. And there are a few tools to do this. I think we should first introduce the idea of equalization. It's a fancy way of saying, look, I'm going to lose half the signal like down the line.

15:38So what if I just boost the signal twice now so that by the time it reaches that point, it will still be like what it was here because I amplified it beforehand. And so that when it degrades later, I can, I can, uh, keep the voltage level constant, right? So that is equalization. You're basically applying the inverse of what will happen to the actual signal, right? So, okay. Let me, let me interject really quick. So back to the eye diagram. So you're saying the problem is the eye starts to collapse, especially if we just don't do anything, but we're increasing the speeds, of course, it's copper.

16:17And so kind of the distance at which you can effectively like keep the eye open is shrinking. And so the question is, you know, how do we keep the eye open? And you're saying like, one of the simplest ways is sort of like, hey, if we know that it's going to like attenuate or degrade as it goes through, can we just amplify it? And it's kind of like, if you and I were in a hallway, and I was talking to you, and then you went and went a lot farther away, I would just shout so that by the time it got to you, it would sound normal. Yeah, exactly. That's a good analogy because you can kind of see how far away that person is and there's no point talking softly because you know they're not going to hear it.

16:55So you would like adjust your volume to be good enough so that you have a good chance of them hearing it at the other end. Yeah, exactly. That's a good analogy. I like it. That's on the transmitter side though. That's what you can do by shouting in louder. But what can the receiver do? What can the person on the other end do right that's that's what like what you will often see as ctle is is called continuous time linear equalizer okay so this is like a long acronym but it's in concept it's relatively simple okay it is just that you want to amplify the high voltages more compared to the low voltages so that you can kind of stretch the eye open.

17:41Imagine that you have, remember I told you that 0.75 or above is a 1. Now, what if you can just amplify the 0.75 to make it 0.9 so that the eye is even more open? And what if you can make the 0.25, 0.1? So now your eye is like much nicer and much wider open. So you can amplify the highs while keeping the lows low. So that's one way the receiver can deal with this problem of all these channel imperfections that happen. This is still analog stuff. Okay, there's no like digital work going on. This is just a simple amplifier. But the problem with this is that it amplifies all the high frequency noise stuff.

18:23Like if there's any noise and all that, everything gets amplified because it's just a dumb amplifier. Like it amplifies high signals and keeping the low signals low. That's it. That's not a good thing. And if there is any interference from the neighboring bits moving up and down, it'll amplify that as well. So it's not entirely very clever, but it's a necessary part of the system. Yeah, it reminds me sort of like naively, like if I'm the receiver, if you're at the other end, and we got far away, and you shouted, and then I can kind of hear you, but instead, I'd like put headphones on, and I just hold a microphone.

18:59And then the microphone sort of like does that, it like hears you, and I turn up the gain or something and it's like oh okay what you said at one volt was down at like 0.75 by the time but then this microphone just amplified it back up to one volt and i can hear it fine yeah yeah yeah exactly exactly so now there are other other ways there's one other way we can do one other thing we can do with the receiver i think it's a little bit important and this is uh this is the clever one so what this does is remember that it's a very good question you asked me before as to which of these errors intersymbol interference or jitter is like deterministic.

19:33And the fact that intersymbol interference is deterministic actually helps because you can predict, you know, how this spreading of the square pulse into hills happens beforehand by running some tests on the channel and you know how it spreads. And then you can like back calculate and subtract it out of the received signal because you know how much spreading has happened. And so you add it back or subtract it back and you reconstruct the waveform. This is called a decision feedback equalizer. So it just knows what's going to happen in inter-symbol interference and it cancels it out. Gotcha. Nice.

20:13That is pretty clever. So does it look at like, it depends on like what I just received, like, oh, I know that I just received one, one, zero, one, and therefore I can calculate sort of in real time, what kind of like noise or smearing or interference I would get from that particular pattern based on this particular channel? Yeah. So it has some kind of a characterization and then it reconstructs it based on how much it knows the spreading or the smearing has happened. Very clever stuff, very complicated stuff. And it is because of this that even Gen 5 PCIe works. is a very essential component.

20:54These DREs are very essential components, right? Does that, really quick, does that have to get tuned in manufacturing like per board or something? I think it does. Yeah, I think it does. Interesting. So it's not all that straightforward to do, but it is a system that's been around a while. So it's not like ultra new, but these are all like very clever chip design techniques. You know, there are these, I have some friends who actually do this for a living and they're really good at it. They're like these analog guys. They're awesome. Okay, so, and when you go to these conferences like ISSEC and all that, you'll see all these designs of how they do this.

21:31It's quite complicated, let's just say. We're just trying to cover it at like an extremely superficial level, but the reality is very, very hard. Finally, I think it also extracts what is called a clock and data recovery. So what that means is whenever, let's say I'll be like, Austin, whenever you see a symbol go by, just clap. Okay, just clap for me. And I'm going to sit here and kind of write down all the times that you clapped. And I'll be like, okay, I know the period of the symbol. I know the clock now. So now I can set like a metronome. You know what a metronome is? It's like that music thing that goes click, click, click, click.

22:11So I can set the speed on my metronome. And that should work out well, because now I know when bits are coming just by hearing the sound. So I have recovered the clock this way, right? That's pretty clever. And that kind of helps with that problem that we talked about where it's like, if I'm on a particular clock and stuff isn't flying by right when I expect, I'm like, man, this isn't lining up. But you're saying, no, no, do the opposite. Just watch what's happening and then figure out the clock from that. Yeah, figure out the clock. So this is all, these are all the techniques that people use to correct it.

22:41And pretty much this is all there is to it. So you can do the, just to quickly summarize, you can do the equalization at the transmitter thing. Remember you said like, just shout louder, you know, or you can do at the receiver side, you can do the equalizer on the receiver side, which is like, just put a little amplifier or some microphone and turn it up. Or you can do the decision feedback equalizer, which is, you know, what the smearing is happening. I don't think we have a very good analogy for this, but you know, you can reconstruct based on the inter-symbol interference. And finally, you have to recover the clock too by, you know, basically clapping out and fitting a metronome to it or something and you figure out the clock.

23:18With all this information, you can kind of tell to a high degree of accuracy what the received signal is going to be doing. And you can correct for errors with these methods. And that is essentially with all these build up a full, you know, PCIe channel in the transmitter and receiver and with this chain you can build what is called a retimer. So, and I wanted to also mention the clock and data, clock recovery process, because it retimes the signal, right? And I'll tell you what that does in just a minute. So, now I'm going to just explain what is a redriver and what is a retimer, because there is a difference here.

24:00Okay, so Redriver has, it does everything that I just said, but it does not do the clock and data recovery part. And it also does not do the decision feedback equalizing, because I think it needs some amount of like sophistication to do that. So imagine you're just shouting louder and you're using an amplifier on the other end or a microphone and picking up the signals better. That is called a re-driver. It is just an analog megaphone. That's it. Yeah, you're just driving the signal on one end of the other. Yeah. So what are the benefits of this? Yeah, it uses lesser power and energy. It's less complicated.

24:45You know, a re-driver is simpler and things are good. That's it, you know. And you don't have much latency. You can do this quickly. Low energy, all that stuff. But the downside is that when you go to faster and faster signals, you have more and more crazy things happening to the signal, you can't recover it. So now what do you do? You have to go for the whole enchilada and go for full retiming where you get the decision feedback equalizing to remove intersymbol interference. You recover the clock. So it's not just that you amplified it, but the retiming process basically accumulates all these bits and sorts them nicely into the windows they're supposed to be in.

25:30Because you remember, you have the metronome clock. So you know where the bits should lie because the clock that you recovered tells you where they should lie. So you can take these bits that arrived late or that got messed up somehow and slot them into the correct time slots. And now you have a beautifully recovered signal because you took the bits you received and you put it on where the clock should be. So you retime the received signal based on your recovered clock. Yes. Okay, okay. So to sort of simplify it, like back in the analogy of like when you and I spread out, the further out we go, I shout louder, you have a little microphone and headphones, but eventually it just doesn't work.

26:11And so, because whatever, in this analogy, we're just too far apart. And so this essentially with the re-timer, are we ultimately just putting someone in between us and like I'm shouting and they're listening to what I was trying to say and then they're sort of cleanly repeating what I was saying down to you? I think it's a little bit different. That sounds like it's more like a repeater to me, a repeater amplifier to me. This is not really that. This is like somebody who knows what is going to be said on the other end to some extent. Like, I'm going to talk to you about, you know, retimers. And you are an expert on retimers.

27:01And so even if you hear it faintly, you kind of have an idea of what it is that is being said. When you hear a garbled word, you're going to be like, oh, he's talking about retimers. So he probably meant clock and data recovery. Because a general person who is not familiar with the domain would not understand that word. but because you heard it halfway and you know the context, you can kind of reconstruct it better than the normal person would. Nice, nice. Very good. Okay, okay. I'm tracking. Okay. I hope everyone else is too. But yeah, so this is very important. So these retimers, now that we got to the point of retiming, these retimers are what make sure that bits from a GPU make it to the NIC so that you can then go do scale out.

27:48or the bits from the GPU make it to the CPU and then you can do all this agentic fancy stuff, right? The bits have to make it from point A to point B. Otherwise, you're not going to have any communication. So this is a problem that essentially Astara Labs solved for NVIDIA and in their HGX baseboard, I think the H100, which is just, it had like eight GPUs in it. They needed to make sure that things can communicate with each other on the board. So that's what this retimer chip did. And it really got off Asterilabs to a running start for sure because you need about a 1 is to 1, I think, a retimer chip for every GPU.

28:35You might even need two on either end. So that's like a fair bit of content that goes into NVIDIA H100. And at the time that HVN1 came out, that was when AI exploded pretty much. And winning this slot was fantastic for the company. Because every hopper tray that was made had Asterix chips in it. Every buddy. And they had a large, even now they have a pretty large market share. So imagine how much money can come out of that business alone. And this was called their Aries series of retimer chips. This was like their first product line. Yes, yes. Okay, let's get into Astera. So what I'm hearing you say is that when NVIDIA exploded and things took off with the Hopper era, for every single GPU that was ever sold, there needed to be a retimer so that the GPU could talk to the Nick, for example.

29:34And my question is, how did a startup own that socket? Where did Astera Labs come from? And how did they get into, presumably, the H100 reference design so that they would get designed in? That's amazing. That feels hard to do, but it's incredible. That's a good question. But these guys, I was looking at the company earlier. All the founders are actually ex-Texas Instruments guys. And they were basically high-speed interface folks. And their ultimate bet was that in 2017, they left TI, I believe. and their bet was that PCIe 5 would be required on every server board. That bet turned out to be right.

30:20Gotcha. So they saw this coming. They said, oh, every server board, even presumably CPUs, would need PCIe Gen 5 and at that speed we think copper is going to fundamentally have a problem and that these retimers will fundamentally be required. Yeah, they foresaw that coming and that as soon as servers go faster, that they're going to have to use these chips. And so they made this whole company. And then it was great when the H100 and the chat GPT revolution happened. It was great for Estera Labs. The question was, when I was researching this, I was like, why not other companies? PCIe has been around a long time, right?

31:05But what's the big deal? Why Estera Labs? Why not Broadcom? Why not even TI? I think one of the smart things they did was they have... I think they were first to PCIe 5 market. So that is one thing. And the other thing I believe is that they have this monitoring platform they built pretty early on called Cosmos, which not only tells you when the link is going down or something is going bad. But all this channel impairments, all this data, all this technical stuff we spoke about, they could capture everything on that platform. And hyperscalers love that stuff too. So I think their software platform had something to do with it as well.

31:54And then when they get qualified, it is a major win because now you're locked in. It's a very sticky slot. Nobody wants to change this stuff if it works, right? Totally, totally. Interesting. So you're saying like when they were seeing that this socket was needed and retimers would be needed, presumably others saw it as well. People who work on the Gen 5 spec, for example, would have known well in advance, hey, we're trying to qualify 32 gigatransfers per second. This is going to be a problem. But Texas Instruments has a huge catalog, for example, and so do other companies. And so they might have just thought just about like the retimer as a component in their catalog.

32:27But what you're saying is maybe Estera thought like, no, it's more than just a retimer. It's also a sensor that can give you health monitoring information about your entire fleet. So we'll capture telemetry. We'll build software around it, give you a user interface. And it's not just a little black box component on your baseboard, but it's actually something that can give you all sorts of insights. So that, for example, if you imagined that the world of tens of thousands, hundreds of thousands, millions of GPUs in a training cluster, imagine if they can all be telling you about the health of their link for example i i can definitely see how obviously that's supremely valuable for the end customer but also that it might take a company oriented around that mindset of this is more than just a little component on a board but obviously it's very customer-centric and then to your point of course sometimes when there's i should say a good time for someone to try to take some market shares to obviously be first to that next generation thing Or create a market.

33:34And of course, if they were there first and they got designed in, then all of a sudden now it's like their socket to lose, even though they're a startup. And again, this is the beauty of fabless companies, which is, you know, your fab partner can manufacture at scale. So if you can get designed in, you can figure out, you know, how to build these things at scale. And now it's sort of your game to lose. Yeah, this is the benefit of startups, right? They can pick a problem and just go after it. bigger companies are not as nimble. And that's one of the nice things about this industry that somebody can come in and disrupt something amazingly different.

34:07And which is why we would love to, you know, also talk to startups on the podcast and stuff. This is a very interesting industry because Broadcom did come in later as a second source. They did come up with a similar retimer chip for doing Gen 5 timers in 2024. but by the time when you're designed in, you're designed in, right? Like it's hard to move because the NVIDIA will have to requalify everything and they have to make sure that the channel link budgets are correct. It's like a big problem. Once you're designed in and it works, you're done. So the question is, did Asera keep the slot when Hopper went to Blackwell?

34:46Yeah, they did actually. They did keep it in the B200 boards as well. And I believe it was the Ares 6, which is the Gen 6 part of the same family, which was doing 64 giga transfers with PAM4. So they had like a fancier chip, of course. This chip has more ASP, good for money, right? Yeah, yeah. So all through, you know, every time they sell these chips, the revenue keeps going up and up and up, you know. So you can see all these charts probably elsewhere. Like people are charting all these revenue tramps, right? Like for Astara Labs. so it's all public information. But yeah, but one interesting thing that happened in the Blackwell era was people got a little spooked because NVIDIA said like, okay, this is not happening, guys.

35:35Like the distance between the NIC and the GPU is too far. So we're going to move it close by. And now everybody like freaked out because what does that mean for Astero Labs, right? Now, if you put them close together, why do you need like Gen 6? I don't know, some fancy retimer chip or maybe you don't even need retiming. If it's close enough, maybe you just go with a re-driver, cheaper chip, lower power, all well and good. So that was a bit of a scare. But as reality would have it, it turned out differently. Do you want to know how? Yeah, yeah. So what happened was, it turns out that not everybody deployed racks this way.

36:19the the the grace platform the grace blackwell platform uh had variations like there were a lot of customized deployments going on for whatever reason i don't fully understand why there were customizations but everybody didn't use nvidia's so-called reference design where things were placed in a certain way there were customizations as soon as customization started to happen it wasn't if the reach went up again and so the retimers were required and then the second thing happened, which is the birth of like custom accelerators, like XPU, the Tranium thing, you know, all of that came in. And once all that came in, like, you're not no longer tied only to NVIDIA.

36:58Like the ASIC world is wide open for you. You can go and do, put retimer chips in all of those accelerators. Yeah, absolutely. Totally. There's a new TAM for you. And I could see, you know, once people got used to having the retimers and the telemetry information, it might also be a little scary to take that information away even if nvidia said oh if you you if you put everything close together in our nvl 72 um configuration our reference design you won't need it it'll be great but i could i could see being like no no i think we do want to pay to have that telemetry and to make sure those signals are clean yeah yeah yeah exactly so i have some numbers actually so in 2023 their revenue was about 115 million after their hopper thing took off in 2024 they were at nearly 400 million and in 2025 they moved to other product lines which we will also briefly mention right after this they were at 850 million for 2025 and in Q1 2026 my note says that it is they're already at about 300 million and it's just the first quarter so you're like looking at a company that's going to do over a billion in revenue now so all these are revenue numbers by the way so yeah so you're looking at a company that you know revenue just three years ago was a hundred million and now they're at a billion it's an interesting story and it's this general story of you know how retimers and how getting the signal from just a GPU to the other end of the line, whether it's a CPU or a NIC, could make a company a billion dollars, right?

38:41It's quite a nice story. That's amazing. So, of course, one must ask, is it just retimers or is there life beyond retimers? There is life beyond retimers because this is where their next big move is, really. you know the big socket that you mentioned in the cold open basically is that they're like why why stay within why stay within the tray right like we know how to condition signals why don't we go up and make a full switch we'll make a switch you know and this is competing with basically the NV switch or it's competing with the Broadcom Tomahawk switches so they have their Scorpio I believe P and the Scorpio X switches.

39:32The P is basically for scale out. So this is going to be pretty much a Tomahawk replacement switch. And they have a Scorpio P series switch with up to like 320 lanes. It's a very high RIDIC switch. And then the X series that they have is basically for scale up, it's like the NV switch replacement that like anybody else could do with like merchant silicon. So NV switch is basically NVLink and NVIDIA's switch, right? But if you wanted a similar performing thing, you could do Scorpio X. So there's that. Yeah, totally. So you're saying, as Tara said, hey, what are our core competencies? It's networking, but it's signal conditioning.

40:19and we're doing that really well with retimers, but ultimately let's move into switches. Is that because conceptually a switch is like signal conditioning of every lane plus routing or something? So like, is it pretty conceptually similar? Yes, the signal conditioning part is, but then there's actual switching process in packets and stuff isn't very simple, that straightforward. Because so far we're just talking about signal conditioning, but how the packet is actually switched within a Scorpio switch isn't that straightforward. It's literally like how to build switches, right? And this complexity, because it's not incremental, is exactly what makes this a very high ASP part.

41:05Like they expect a lot of revenue from the Scorpio switches because I believe the Terranium 3 uses this Scorpio X as well in scale up. So yeah, it's probably going to be quite a bit of revenue from the Scorpio parts going forward. Speaking of Tranium, does Amazon have warrants in Astera Labs? I feel like a lot of times, I'll have to look it up. I think they do. I think a lot of times when a company like Amazon works with a very early stage company like Astera Labs, they also to make sure that all their incentives are aligned they end up getting some warrants or some ownership of the company and that that obviously can help okay astara get the opportunity to build out their port silicon portfolio and have the get the right to play in train in future tranium and then of course um it maybe incentivizes amazon to put astara silicon in in their silicon when they can instead of, for example, Broadcom.

42:17Yeah, yeah, yeah. Oh, I mean, there's another big story there which I'll briefly mention because it's really interesting. Because, you know, so AMD actually wanted to put, because they are all about UA link, right? Like the open standard of hooking stuff up. AMD actually wanted to put a UA link switch, but there was no UA link switch in the market. So what Broadcom did was they were like, okay this is the only thing that was available was a broadcom tomahawk switch outside of like nvidia's nv switch or whatever so there's no option amd had to go with broadcom and so what broadcom did like this is what this is ruthless business right what broadcom did was they immediately exited the ua link consortium and they're like ethernet is it you know they had like scale up ethernet sue and then they merged it with like ocp and called it esan and they were like that's it you know we're not doing ua link we are in if you are designed in with us we're going to go ethernet all the way it's basically puts you know the nail in the coffin for all these other people who are trying to do ua link and they're like no we have the only switch in the market and we're not doing ua link screw that like we're going you know ethernet that's it no more and remember the tranium thing with the scorpio switch right now is uh is a pcie switch it's not Ethernet PCIe could be used for all this as well by the way and Amazon Tranium is running on PCIe but the future of Scorpio switches actually has UA link in there and it's probably a 2027 I think story along with Marvel who's also building something like this for UA link now the risk here is like will AMD and the others go away from using Ethernet eSun and go jump on UALink and buy all these people's switches or are they going to say no forget it Ethernet is it we have been designed it remember Astara Labs own story right when they got the Aries slot on the Hopper series Broadcom couldn't nudge them out now what has happened Broadcom took the AMD slot because there was nothing else in the market and now they've cornered the Ethernet way and exited the UALink consortium now How can they get back in?

44:39That's very interesting to see. Yeah, well, we should do a deep dive on this because I know that with the Helios platform, AMD is doing UALOE, UAL, UALink over Ethernet. And so they're using like the UALink protocol, but they're doing it over an Ethernet switch. And so I do think they're planning to take a step in that next gen of Helios to moving to UALink. But to your point, Astaire Labs in the market didn't have the UA link switch ready in time. So this is like an intermediate step. So I think that Helios 500 and beyond will be interesting to help tell us what direction things go. Yeah, for sure.

45:18UA link is supposed to be the more purer networking.

45:25GPUs, you can access each other's memory and all that nicely with the UA link protocol. It's built for this kind of stuff. It's very low overhead, very lightweight protocol. So Ethernet and eSun and all these are like kind of derived from the previous era of Ethernet and is not optimized for what AI needs today. UA-Link is more so. So we'll have to talk about these standards another day because that's like a whole different subject. But I just wanted to like mention like the two other things that it's only a mention. I think Astera Labs has their Taurus product line, which is essentially basically the same signal conditioning product, but you put it inside cable and you make an active electrical cable out of it, like AECs.

46:14So they have like these chips that they can put in AEC cables. This is not like a high margin business. And they are very clear that look, our gross margins may go down because this is not a high margin business, but we want to do it anyway. Like if there's a way we can use our existing technology, we will, right? So they're like, we'll do it. And then their newest line, I think, is the Leo product line, which is basically a CXL controller, which is used to maybe pool memory and do that kind of stuff. So that's still new. But there is some promise. There are apparently some design wins already.

46:52So we have to keep a tab on that. CXL is a new topic, a new episode for another day. Totally, totally. CXL is old, but it's new and it's coming back. Maybe we'll talk about it in our time. But with that, listeners, we hope that you learned a lot about retimers. We hope that you learned a lot about Astaire Labs and you had fun with it like we did. So thanks for listening. Check us out on YouTube. Leave us comments. Share this with your friends. Check us out on Spotify, Apple Podcasts, wherever you listen. And of course, check us out on X. We're trying to post this, of course, on X, as well as our daily takes.

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