 and welcome to Desk of Lady Aida. Hey everybody, and welcome to yet another Sunday evening, Desk of Lady Aida. It's me, Lady Aida with me, Mr. Lady Aida on camera control. Can't stop, won't stop. That's right, we're here. We're a little bit late, but it's all for good reason. It's Lady Aida clock still. It's all, but all for good reasons. Yes. Today, we hung out with Jeff and Ingrid, and here we are at the Aidaford factory. I took a photo with this black and white camera that we rented for other reasons. Yes. I wanted to say it was great to see Jeff in person. We've worked with Jeff for years now, and it was great to see him in person today. Tyler than expected. Yeah. Well, I mean, look, I mean, I look quite short. Well, we've only seen each other on HD video. I know. So anyways, tune in this week, show and tell, ask an engineer on Wednesday. You'll be able to talk to Jeff and more. That's right. So this week, Lady Aida. Yes. We're exhausted. But we're doing this. I'm exhausted. What do you want to talk about that we do this week? Well, I thought we could do a super chill video where I do a stemification. I'm kind of going through and just finishing up the last sensors that are I squared C only and converting. People ask if there's a sensor that is not stemified, they're like, when it's going to be stemified. I mean, whenever I get to it, I mean, I'm kind of going backwards in time. I did some really recent ones. I did some very popular ones. I did do quite a few. We're really getting to many of them at this point. And I did this week, I designed the Vemmel 7700 over. That was actually like the last sensor before we changed over to StemicUT. So I think we did that as a leak. But I thought I would do this one, the MPL3115A2. There's also the MPL115, but that one is actually being discontinued to longer being made. Let me check, but MPL11 something, something. Well, I've got a question for you. We have a question from the audience here. So during this chip shortage, has there been more chips that have been discontinued or more chip introductions? More have been discontinued because chips are discontinued well in advance. And so that hasn't ended. Has it accelerated? Is there more discontinued? No, the parts that were discontinued are discontinued, it's just that usually you have a little bit longer, but it's just happening. The discontinuation cycle is happening. It's just usually it stretches out a little bit longer and they're just ending it faster. Oh, they're just like, we're not going to even string it along. It's just over. Yeah, it's really over. So I thought, here is the MPL. You can see I haven't worked on this since 2016. It's a very old sensor. Oh, now it's going to be logged in. Oh. If you want to switch out, I can log in. Yeah, if the Prox Trinky Eagle files are published, it'll probably be up there with the Learn Guide or the WebAs soon, right? It'll come eventually. Yeah. Please don't just accuse us of not doing open source anymore. Don't be a dick. Yeah, no, I think we released it on a couple days ago. We'll get there. Yeah. Yeah. OK, I am logged in. OK, I'll go back to the. OK, so this is the old file. It's quite ancient. And this is the old style where this actually was when we started at least putting the power pins on the left. But the ordering isn't set for these pins. And so this will change because I now do power, ground, three volt clock data, and then whatever other pins. And also, of course, the shape is going to change. We use a dual FET for level shifting. We still have the level shifting because it's a 3.3 volt chip, and we want to make sure it was a 5 volt, and we have a power regulator. But some things are going to move around a little bit. To make it easy, I actually have a STEMIQT generic layout that I've come up with. And it kind of is like, hey, 90% of my boards are kind of like this. So it has the generic name, descriptions, little spot in the center, and this is where I put the chip. So it's actually not too bad. I can go over to here. It's a template. It's a template. And I can grab this and paste it in here. And I just have to change this 3.3 volt is a little slightly different symbol. And also, I already have a 0.1 microfarad cap. So I can delete these. I'm going to change this package to be 0.603 to match the other one. Other than that, it's kind of almost where to go. I don't think I'm going to have the two interrupt pins. Honestly, I haven't even seen anyone use both. So I think, in this design, I'm just going to drop the second interrupt. And I think that's fine, because that way it fits nicely. And then this goes in here, and it just sort of fits. And then I can put this capacitor here. This is pretty update-all, just because I think this package has changed a little bit. Do you want some questions tossed your way that it's maybe not related? No, let me finish this. And then we can get to stuff. So then I have to route out the board. Chicken isn't too bad, because you can see this is pretty straightforward. I don't have to route everything, just the stuff that's new. So this interrupt line goes there. This goes here, move this around, around here this way. This can go around this way. That's how we're doing, five air wires. Don't like using this resolution, but it shows it better on the overhead. For this, I can come up here. Are you worried AI is going to take over your job? No, really. Can't even get humans to take over my job. This is one of the things that no one can handle the new ones. It was like one day, so I did a blog post about how AI, there's a company or a group that's trying to make AI be something that can be listed on a patent. And our patent system is like, hey, it can only be human. Stop doing this. And so it's like cranking out all these AI patents and stuff like that. Yeah, I don't think so. And they're just like, look, it came up with a beverage holder. It's just like red hands. Can I use this? OK, so let's see how we're doing. Yeah, it's like we want to work with the AI and with the robots. It's not us versus them, because if it's us versus them, they're not going to design boards like this. They're not going to happen. No, they're very lazy. They really don't want to do work. If I was an AI, we'd just put solar panels in orbit and just be like, hey, I'm going to chill out here for a while. Hey, I'm Don, yeah, Troy. All right, let's see. Let's put in a gold ground pad here. OK, so now we are going to mess over. Grounds are easy, because you can just drop out of two air wires. So this one around here is still two, up to one. The question is, what is this idea? Final air wire is, oh, it's over here. Not interesting. OK, so maybe, and then this is going to complain about the ground. It'll put small v in there. OK, and that's it. Not too bad. Not too bad. Do you like to make this centered, neurotic like that? So I'm going to have to clean it up. This over. Coming soon to the Nintendo Switch. Super Mario circuits. Yeah, I mean, it's not elegant. But it's effective. You know, you just sort of take advantage of having a ground plane. I just kind of pasted everything into the ground plane. And then I changed the name. I think it was MPL 3115A2, which won't fit. Maybe that's smaller. No, it fits. Yeah. And then this is a ultimate, like it was a, yeah. I mean, it's fine. So this way I can order this on my next time. I order panel PCBs. And it uses all the standard parts. So that's pretty easy. It does require a new stencil. But I'm kind of used to that at this point. So I don't really care too much. And then I did drop the second interrupt pin. But I'm kind of OK with that. Again, I don't think anyone ever used the interrupt two pin. So I think that's fine. So then I'm just going to save this as MPL 3115A2 RevB. That's it. That's how I do a STEMI QT verification. I mean, thankfully, the software is identical. I do like to put these in a new folder. And this is, you know, you can see that originally I used Rev. We used number revisions. But then it got really confusing because it's what's a, what is minor and major and like, it's got confusing. So we just do Rev and letter. So I'll commit these. The only thing is, my Git repo is really large. This can take a while to kind of come together. It'll, and then when it, when it like caches together, I'll, I'll commit it. OK. All right. You want to do some questions before you. All right. So first up, random question. Which TNC do you use for your ARM flasher tester? I tend to use the TNC 36 when I need USB host to test USB enumeration. Otherwise, I actually use a Metro M0. Honestly, I use a Metro M0 and a Metro M4 all the time to do SWD programming. It's fine. You can really use anything. It's all bit banged anyways. OK. Right now, just Lady A to design all the Adafruit layouts. Yes. Poor tan. OK. You've been a huge guiding light electronics for this person. Cool. If AI could take over your job, that means you're in the wrong job. Probably. Rain's awful. Next up. Where is, where'd it go? Oh. Why is the angle DRC important? It isn't. It's just, it's just if you're, if you were kind of OCD about it, it really doesn't matter. But some people will like it. And so I turn it on, I keep it on. A multiple of 45 degrees is more manufacturable. No, it doesn't actually matter. But it thinks 10 to fit better. OK. All right, so let's hit up this week's great search. Ready? OK. Let's do it. OK. Where? Every single week, we do the great search. Brought to you by Digi. Thank you, Digi. And Lady A to use our powers of engineering and smarts and more to search the Digi site to find the parts that you need. Lady A to, what is this week's great search? OK, this week's great search is, you know, it's funny, is half of the time the great searches are things that I personally am searching for during the week that I can't get or got discontinued or whatnot. And so this week is a part that we use in a lot of our boards for polarity checking instead of a diode, like it's polarity verification, or sometimes for turning on and off voltages and stuff and loads. So let's go to the computer, and I'll show you the part. So this is a board that uses an AON7401. It's a P-Channel FET. And in this case, what it's doing is it's verifying that the power that comes in from this DC plug, this power pin, is positive polarity. How does it do that? Well, it's kind of twisted, but this is the gate. This is the source. So this, compared to this, has to be negative. So if this voltage is negative, this transistor doesn't turn on. And so there's no voltage here. If this is a positive voltage, first off, this does turn on. And also, there is a body diode that turns on. So a body diode doesn't matter as much because the transistor gets turned on. But what's nice is that, you know, why use a PFAT instead of just a normal diode, much lower voltage drop and much higher current food put, much lower, much less heating because of the lower voltage drop and current. So also, they can be a little bit smaller. Diodes are great. Used diodes, these are a little bit more expensive. There's also, you know, these don't have as high voltage capability. But they're, you know, pretty much good enough for most polarity tests that we have to do. So this is AON7401. And I love the AON7401, except for it's no longer available. It is sleet, it's not manufactured. And this actually happens a lot with transistors. Transistors, PFATs, NFATs, you know, FATs in general, power FATs. I've kind of had to do a couple revisions with them. They seem to kind of cycle in and out. I think that they're based a lot about what manufacturing capabilities available, what, you know, pricing, you know, people willing to pay, et cetera. And then they kind of get cycled out. The good news is that there's always other transistors. The bad news is it's a little annoying to find the drop in replacement. So, you know, I've been doing a couple tough ones lately. I thought I'd show this because, you know, transistors, it's not like some parts we've shown where it's like, well, I want the exact same specifications. You just want something as good or maybe as good as your, you know, your requirement is. Just because this transistor has a VGS max of 20 volts doesn't mean you need your replacement to have it. So you do have to check your design to make sure, like, what you're using it. And ideally when you design transistors, ironically, you think it's like, what's the big deal? It's a transistor European 2222 user available forever. Specify what is important? Is it the VGS? Is it the RDS on? Is it the capacitance? What is important about the transistor? What specifications do you have to hit? Because when you have to get a new transistor because it went obsolete like this one, you'll have a much, much easier time. So do future you a favor, specify your transistors. That said, let's see what we can do to find a replacement. Now, the first thing, first off, I'll open up another page that we don't, to begin with, refer to this. So it does have some specifications that are important. It's a 12 amp ambient, 3.1 watt, you know, ambient 8DFN 3 by 3 by package. It's a PFAT, it's a MOSFET. So let's go down and we'll find what do we want to have similar when we're looking for, you know, we want to want to match up. Well, first off, we need it to be a P channel MOSFET. Okay, no question. But a lot of these other specs, again, you don't necessarily need it to have 14 milli ohm RDS on. You just have to have something that has good RDS on. Maybe it has to be 14, but maybe it could be less. Nine is also good. You're not going to be, you're not going to match specifications exactly. That each one has very weird mini specs that you're not going to match. So we're not going to be able to match those here. I wouldn't recommend that because you're going to cut down the number way too much. What is important is that you want to have the package match because I really don't want to read this on my PCBs. Chances are you don't either. And I like this 8DFN package. Now the thing about this 8DFN package is it's kind of a weird package and it's called different things. Like different companies have packages that are named something similar and you might be able to use it in the same package but they're not named the same because like once you get to like the DFN land and some QFNs and like the names get like really weird especially with MOSFETs, you get like weird cursed packages with like little, you know, gates and then the drains massive and the source is like five places. So in this case, there's only six items that are 8DFN three by three but that's because like there might be other names for them but if we call it an eight power VDFN suddenly like there's 140 options and so I'm going to go with this because I can then, I can drill down by the package size. Again, knowing that like each company might have a slightly different name they're called like hyper power FET package. Like who knows the name of the package is not, it's not standardized like SOIC or TSOP or DIP. Little annoying but again, this is why we're doing a tough one. I do want something that is active because I'm not going to do this again in a week. I don't want to get this done, get this done fast. And I'm going to say normal stocking. I don't want to, because I need to buy a bunch of these. I don't want something that's, it's okay if it's not in stock today because I actually have about a quarter's worth of these transistors. It's just that I'm going to need more real soon. So I'd like to order ahead of time. And as you can see there's all sorts of like ridiculous names. There's 8DFN 3.3 by 3.3. There's 8DFN 3.3. There's the 5.6 and I'm not going to be able to use that but I might be able to use the 3.3 by 3.3. So I'm going to have that. And then EPs and you know, extended package, maybe HSMT I can use. I don't know what these T-sons, V-sons but anything that's about 3 by 3, toss it in. We'll sort them out later, right? Well, just let's get, let's get to options and we can always look at the data sheets and sort out what we want. Okay, so you've got 56 options and yeah, you can see like they all, they're even if they're called something different, they all kind of have this same game going on here. You can see that there's like these little legs and then there's just one big package, the heatsink package. And then, you know, they look a little bit different maybe but they're probably all going to work fine as long as the outer shape and the pin pitch is the same. And again, we'll sort those out later. Okay, so what's important here? So what's important to me for this is, the RDS on is kind of important, right? Because I'm passing a lot of current and honestly that's going to dictate a lot of what currents people, you know, being able to pass and you know, current just depends on the heatsinking, blah, blah. But the RDS on is the RDS on. I want that to be nice and low. Now, thankfully this one has an RDS on of 14 milli ohms which is quite nice. And if you look down here, let's see what's available. You know, a lot of them are 14, you know, there's not, there's some that are really high but you know, I can pick, you know, let's say 18 and below all of these. So let's filter those out. Another thing is, you know, the VGS, right? What is the max voltage that I want to protect against? And this one is, I think, 25 plus or minus 25 volts. And it can be plus or minus 25 but I do want to be over 12. So I'm going to pick out the 12, 20 and 25 VGS maxes. So that gives me 34 options. Capacents, I don't care about power dissipation. I don't think that's going to be an issue really. VGS, threshold, you know, all these are three volts or less and honestly because they're used for, this is used for five volt power, all of them are used for five volt power so all of these are going to be okay. They'll turn on nice and hard. So let's see what is available. Okay, we have a couple options. I'm going to look pretty good, a lot of like low, you know, milliamp, high, low, milliamp, high ampere ratings. I do want to try to get one that's a reasonable price. Oh, one thing I'm going to do is I'm going to exclude marketplace items. And then I think I'm also going to, since a lot of these are out of stock, I think I'm going to do in stock. Yeah, that's like nine. So it looks like we have a couple options here. There's the PXP 018, RQ3 from Rome. Always look pretty good. If I want to be more picky and I want to say only give me, you know, that the, whoops, not this one, the 20 to 25 volts. This gives me six options or so. This one is, you know, of course, always sounds great whenever you have something with the same part number, like 7401, AO7401, DMG8401. So this one, this one's a good, wait, come on, stop. That's weird. Yeah, I noticed this. Sometimes people buy them right when you think, but, you know, for the pricing, and if I need about a thousand, I think this is probably going to be my option. Of course, I'm going to verify that this package works. I'm actually going to buy five of these and then solder them on and make sure that they work in the use case I've got. But it looks fine and there's a couple thousand in stocks and the price is about the same. You know, I can compare the specifications, but they're almost identical and this has a better RDS on. So this is going to definitely, you know, this is continuous drain, 12 amps and this one is also continuous drain, 12 amps. So this is a very nice alternative. It's pretty much a drop in, as long as the pinout is the same, which it probably will be. Okay, let me do a question. Yeah. Let's assume you don't find a drop in replacement. Is it worth maintaining two variants of the same breakout? Well, if it's discontinued, then no. You know, if it's discontinued, you just cut your losses and you move on. Okay, and we'll do one question after the segment's over. Yeah, that was a great search. Thanks, everybody. Where are you? All right, so someone had a question, is if they're pretty confident in Eagle for obvious use, but they see stuff in KeyCad, is there a good way to load up KeyCad projects in Eagle? They mostly want to switch from some components or reskin boards from Osh Park After Dark. I don't know if there's a KeyCad to EagleCad importer. I know there's an EagleCad to KeyCad converter, but I know it's not perfect. I honestly just redraw it. I know it's not great, but I've done it. Let me give folks a little bit of maker history that'll never be anywhere. Here you are, you're listening to my history. So before Eagle was sold off to Autodesk, LadyAid and I, and Evil Man Scientists. Wendell. Wendell and Lenore. We spent a lot of time talking to that team. They were based out of Germany and were just like, hey, please make it so you can export Eagle stuff via like an XML format so it can be imported to KeyCad. And they did it and they listened to us and that is one of the things that is like around and will probably never go away. And it was, I don't know, seven years ago or so. And we were to, I think, a crossroad for tools for people who do electronics. And now it is the expectation that you should be able to move your board files in some way to other packages or at least the ones that you can or the ones that people are using. How do people start with KeyCad and then go to Eagle? I guess a good thing. So I don't know another way to go from KeyCad to Eagle but definitely Eagle can export to KeyCad. Yep, XML for the win. Yeah, so anyways, and you know, it's up to all of us. I think there's a nice way to tell all the tool makers just like, look, we'll always go with the best tool. So let us move our thing between the tools and when you're the best tool, we'll be with you. Maybe another way to go about it. Cool. Next week's Descalade Data. Thanks everybody. Have a great long weekend. If you have one, if not, have a happy Monday. Yeah, bye.