 And welcome to the desk lady, everybody and welcome to my desk. It's it's been a little bit of a rainy Sunday also we have a sick kiddo so we're gonna make it a pretty quick episode but I did do a lot of hardware yesterday and a little bit of today so let's jump right into it. Okay so let's go to my computer and I'll show off some of these designs. So the first design that I worked on is for this board called the LTC. I keep forgetting what this screen is smaller solutions. I'm gonna close these things. This is called the LTC 4316. It's a very interesting chip. This is an iSquared C address translator and basically what it does is it looks for like that first byte that's sent over an iSquared C data bus where like the controller is trying to address the peripheral you know address 10 or 25 or 77 and it will XOR in a up to 7 bits of bit flipping to invert certain bits from like 0 to 1 or 1 to 0 and basically like seamlessly translate that address to a different byte. So for example you want to connect to a bunch of VL53L1X's it's like a proximity sensor and you want like eight of them or you can use a multiplexer iSquared C multiplexer or maybe you don't want to use a multiplexer in that case you could use this chip in between each device seven of them so like one would be the original device and then the iSquared C address translator would go in between the other seven and you would like flip a bit here and there you know until you have a different address for each device and then in your driver you just tell it hey look for this address not the original like 0x29 or 39 or whatever. So the only thing that's a little annoying about this device is the way it works is that there's two pins XOR H and XOR L for high and low the highest three bits the lowest four bits and you have to use a resistor divider and you have to it's a linear resistor divider and they're not expected to be adjustable right they expect you to be like okay I fixed the resistors I picked two resistor values to fix the divider and put a certain voltage into here and so the XOR value is you know fixed in hardware but I want to be adjustable so what I ended up having to do is see I wrote with the help of chat GPT for a little script that will let me just create you know do the math to create a divider with parallel resistors like two two optional parallel resistors and then tweak those values until I get like I'm not able to change all seven bits but I can have two bits flippable you know to be customized so here is the divider so for the high bits you know these switches can be off and then these two resistors make the divider and then I can flip either one of these on or off to create like four options that are paralleled with this resistor and then you know I ran it a bunch of times until I got ratios that matched up with the data sheet says are valid options turns out like bits five and six I think are the ones that get flipped it's actually tough because this is a non-resurd dividing and parallelizing is not is non-linear a wizard divider is asymptotic I guess I don't know the word is it's not a linear division because it's r1 over r1 plus r2 not r1 over r2 so you know you can't there isn't any match for combination that will let you have more than like two bits basically I tried three and it just wasn't working out anyway so this is the design that you know what I just realized that my clock is not working anymore the design I came up with with two dip switches and then if you really do need more address bits flipped you can pick a resistor from the data sheet they tell you with values to use to flip any of the other four bits so you you know without any soldering you can do two address changes sorry for address changes two bits and then with another resistor you can do like another like 128 so it's kind of interesting chip so I you know I actually spec this like a couple years ago but again it was one of the part shortage parts I can get for a bit so I dropped it another thing I did is if you remember a few weeks ago I talked about UPDI programming a high voltage programmer with a 12-volt switch in it and then we got an email from someone asking hey can you make a breakout just for that like analog switch because I want to do analog switching and so that actually did it was on my list for a while to do an analog switch breakout so I did a couple things one is I found that there's an I squared C 1 to 8 analog switch available from analog devices that does that's I squared C controlled it has one input that you can select to 8 output you know it's bi-directional but it's an analog switch so you'd be like audio or video or like signals that you want to analyze or whatever you can switch them around and then this is the chip it's a T-SOP and then I just put it on a stem and QT because I squared C controllable it's very simple like you literally just write a byte to the address and that byte says like which bits are which bit is connected right and like this very simple but I think it's still be useful this is a five this one is five volt max is the only trade-off is it's not a high voltage switch but there's still a lot of people I think you have like three or five volts you know logic level signals that they want to switch around so that's the ADG728 and then there is a friend of it the ADG729 same cost almost but not same footprint and this one is a dual 1 to 4 so there's two pins and then for each one can select up to four different connections so it's like so a little bit a little bit different this is for stereo maybe so not as many options per channel but you get two channels I think this one might actually be end up being more popular because I feel like a lot of times people are using this for like stereo audio or something they want to switch it between some sources or whatever so I think this one could be good for that because it's a stereo connection so that's that's the two stem and QT versions and then for a true just analog switch what I did is I made a stem aversion and then I'll I'll do the great search right afterwards one second analog switch in the previous video a few weeks ago the part I picked was like basically the max 4561 and ended up playing with a 4544 because ended up being about the same technically and the cost was you know pretty much the same a little bit less but it seemed like that max 4544 had a little bit more stock available so this one has signal coming in through a JSTPH and then you'll need to give it the V in voltage has to be high enough to be higher than the voltage you're switching so you if you're switching 12 volt voltages you need to have 12 volt power that's normal though and then a terminal block with the SPDT outputs this is what it looks like the signal determines whether the common pace connected to normally output or normally connected and this one can go up to 12 volts but there's no such thing as a 12 volt compatible i-squared c controllable analog switch so you have one you know you know i-squared c addressable so you get like it's so cool because you can like just plug and play it or you can do you know signal to control and it can go up to 12 volts you know and you get more options most of these are signal controllable so those are some of the designs that I've done so let's go to the great search the great search brought to you by digikey and Adafruit thank you digikey every single week later is a power of engineering help you yes you found the things you need on digikey.com later what is on the great search this week okay so this week we had a request for well from me like I'd request 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 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 can use a three volt signal to control SPDD SP DT 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 AGG728 and CV by 728 and 729 those are i-squared c compatible which is like super awesome but they're only 5 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 in 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 maybe not as fast but it's really good for is like your potentiometer signals audio video test signals you know I apparently these are 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 going to 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 the stuff that's through hole which is like a lot of like like 4066 or 4051 type next up 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 this 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 thirteen point two fifteen sixteen twelve fifteen sixteen 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 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 a you know a certain family like the 4051s but one of the trade-offs about these CMOS analog switches is if you look at the datasheet 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 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 there's not gonna 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 want 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 sort by price you have a couple of good options the DG419 TS128 so a couple different ones in the family I did look at a bunch of these all of them were good I'm familiar with the max 4544 so that's what I picked however I will say that like the DG419 is also totally good and a lot of these you know they have equivalent they have equivalent pinouts and then if you look at the VIV 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'm aware of 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 we see it here the V input high no matter what the voltage is 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 because I'm a little familiar with it and it had a lot of stock but I'll say that the DG419 was also good option so you have a couple varieties that are available here but what's nice about this is like the layout was very simple and the usage was very simple so I'm gonna try this out and you 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 thanks for joining us we had a little bit of a baby in the background hanging out asking for bubbles so we did that that's okay yeah baby still a little bit of a call today we'll see everybody throughout the week this week I'm gonna go back to blowing bubbles and we're gonna go and take care of the candle we'll see everybody next week bye everybody bye bye