 Every single week we do the Great Search, brought to you by Digikey, thank you, Digikey, and lady user powers of engineering and smarts and more to search the Digikey site to find the parts that you need, lady, what is this week's Great Search? Okay, 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, you know, 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, you know, 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. Oh, you know, how does it do that? Well, this is, you know, it's kind of twisted, but this is the gate, this is the source, so as long, 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's 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 throughput, much lower, much less heating because of the lower voltage drop and current, so it also, they can be a little bit smaller. You know, diodes are great, use 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 salise, not manufactured and this actually happens a lot with transistors. Transistors, PFATs and FATs, 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 capability is 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 222s are 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 get away to 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 PFET, 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 AP 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 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 PCB, it's a chance that you don't either. And I like this 8DFN package. Now the thing about this 8DFN package is it's like, it's a 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 drill down by the package size. Again, knowing that like each company might have a slightly different name that 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, cause 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 ADFN 3.3 by 3.3. There's ADFN 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 a 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? We'll 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 a 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 this 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, 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 did 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'll have them 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, 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, 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 AO, 7401 DMG, 8401. So this one, this one's a good, wait, non-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 want to, 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 of 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 has 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. Okay. That was a great search. Thanks, everybody.