 The great search brought to you by digikey and Adafruit. Thank you. Did you key every single week ladies repair of engineering help you? Yes, you found the things you need on digikey.com. We need a what is on the great search this week Okay, so this week we had a request for Well from me like I don't quest to make this board, but then I'm the one who's looking for the part I'm looking for a small low-cost analog switch that surface mount and Can can can switch up to 12 volt signals But the signal that's controlling that you use to control it up and down Should be like three volts compatible So basically I can use a three volt signal to control SPDD SPDT 12 volt analog switch and I just talked about a few minutes ago. I was doing a design with I squared C multiplexers and I picked the AGG 728 and See you by 728 and 729 those are I squared C compatible, which is like super awesome But they're only five volt max. I need that 12 volt compatibility. So let's go to digikey and Let's look for analog switch Okay analog switches multiplexers in the multiplexers Sounds good now this difference between an analog and digital switches this one You know if you put audio and you'll get audio out Whereas there are multiplexers that work with digital signal But like I squared C is really common or you are but with those you can't put analog signals in it won't work They're looking for specifically digital like zero to three volts only this is analog switching. So It'll work with digital signals, although it may be not as fast, but it's really good for is like your potentiometer signals audio video Test signals, you know, I apparently these are this like weird every time I look at datasheet for one of these devices It says like ultrasonic like, you know, like sensing stuff where you have Signal coming in from a sensor and you want to switch it around to a different location Okay, so here's all the analog switches multiplexers and multiplexers about 10,000 options So first off, I'm always, you know, I'm always looking for only active Available and I want only surface mount so I'm gonna skip the full ball and I'm going to say normally stocking So that gets rid of like two-thirds of the options just because you know, I'm not I'm not dealing with stuff that's through hole which is like a lot of that like that 4066 or 4051 type next step, I Definitely want to have the Voltage for the power supply remember. I said that has to do at least 12 volts So that's gonna also filter out a lot. There's a lot of three or five volt only devices So let's look so the only thing is is that the supply the way it's done is it has like a little squiggle telling you to and from, you know Above my head. So you actually have to go through and like pick through each one So for example, this one is gonna work. It's one to eight eight one point eight to twelve volts And then this one is ten twelve volts not enough twelve volts two point twelve point sixteen fifteen sixteen twelve twelve twelve thirteen point two fifteen sixteen sixteen Twelve fifteen six is a little tedious, but go through and do them all Fifteen sixteen and then I want to make sure that this works at three point three volts So I'm not gonna go I'm not gonna keep going because then it's like five to twenty volts But it needs to work at three point three. So these are the ones that work within the range. That's another Okay, so now I've got Much fewer like five hundred options Next up, um, I Definitely don't want I don't need like some of these ones that are like multi Connection and stuff. I'll say that one thing you'll notice that there's a lot in like, you know, a certain family like the forty fifty ones but one of the trade-offs about these CMOS Analog switches is if you look at the data sheet Hopefully they'll Come up. Okay They will work at high voltages 12 volt 18 volts, whatever but Should have popped up the data sheet beforehand if you look at the V high for them the V in high which is Quiescent propagation delay Okay V input high voltage in order to trigger it, you know at Ten volts or you know, if you're praying from ten volts You need a seven volt signal to power it just not what I want I want to be able to not power it to signal it I want to signal it with a low voltage like three volts or so and so a lot of those Analog switches that are like the CD 4051 4066 there's not going to work Because of that issue and there's no real way to select them out One thing I'll say is I definitely want like an SBDT So I'm going to just select The SBDT options and then I definitely won't don't want the SPST Which is just like on off. I want to have SBDT for normally open normally closed although I'll grab the DPST, I don't know the other way around and the DPDT also. So let's Filter that out. So it gives me a hundred options And then number of circuits. I really only need one circuit, so let's Let's filter that out and now I've got 26 options. Oh last I'm going to exclude the marketplace just to Get rid of anything that isn't immediately stopped Okay, so now if you start by price, you have a couple of good options. Um, the dg419 ts 12a so a couple different ones in the family um, I did look at A bunch of these all the more good. I'm you know familiar with The max 45 44. So that's what I picked However, um, I will say that like the dg419 is also um Totally good and a lot of these You know, they have equivalent, uh They have equivalent pinouts and then if you look at the vi V input high which is A lot I got to find it in this In Well, I can definitely find it on the max because I remember I looked this this part up Each data sheet it's like you want to find the info and it's not always in the same location so this one V input high so you see it here the v input high no matter what the voltage is um It's going to be Happy at 2.4 volts and so that means I can trigger it for sure from a 3.3 little signal So I did in the end pick the 4544 just because I'm a little familiar with it and it had a lot of stock um, but I'll say that the Dg419 was also a good option. So you have a couple varieties that are available here um, but what's nice about this is like The layout was very simple and the usage was very simple um, so I'm going to try this out and we get a prototype made and probably like in a week or two I'll do a show where I talk about how well it worked Maybe I'll try switching some analog signals around and see how it goes. So that's my pick for the great search