 The great search brought you by digikey and a different things. Did you key? This is one lady uses her power of engineering to help you. Yes, you Find what you are looking for on digikey.com later. What is this week's great search? You'll never believe it, but this one is a part that's been discontinued Available and so we have first time in history. Yeah, I was for this week so far this is last Sunday So this week we are kind of Coming along trying to find a good replacement for a part that's about to be completely unavailable the LC 709 203 our go-to battery monitor chip, so let's Visit Adafruit and we'll show this any chance that battery monitor will make it on a feathery vision We don't know maybe now. Let's explore together Okay, so this is what we've got now the LC 709 So this this monitor is it's out of stock now But it's actually not because it's not a stock. We just sold a bunch this Battery monitor is quite nice because it doesn't use a sensor sister. It's like about a dollar fifty For the chips, which means I can make a whole break out with everything and tested for about seven dollars the original version had a TDF N part and you can kind of barely see it here Which was really nice because it was easy to solder You know eventually that became Unavailable and now we have to use the BGA part, but the BGA parts aren't too bad It's a nine pin BGA, but the center pad Can you know connects to one of the middle pads? So like it's fine? You know, it's basically you're not dealing with okay. How do I get? You know my pads out from underneath BGA The problem is is at this part. I mean, it's it's discontinued. It's still available But it's going to eventually be not available that said it was still because it's just so inexpensive and great It's still been worth it to use. So for example, this is what I originally used It's no longer manufactured no longer available. And so I was like, well, I'm just gonna swap over to the BGA version Also unavailable, but there is you know 18,000 in stock 19,000 in stock and and there's plenty and we don't we've been able to Order enough to last us many years. So we're actually, you know, good for a while, but long term or if something happens To the inventory we have or whatever we will have to Design out or if I'm designing new boards, I'm probably gonna design out to get something else because Stuff that's gonna end of line is is end of line year than it used to be. So I wanted to Show how I sourced a alternative So the price is, you know, about a dollar sixty. So that's kind of what I'm dealing with For, you know, competition for this part. I want something that ideally isn't BGA And if it is Not having to use the middle pads because I really want to stick to some low-cost two layer boards I don't want to have to go to four four layer or like buried vias or plug vias or whatever lithium ion lithium polymer battery Single cell is fine and I want it to be I squared C So looking at the options here, I want the battery monitor with one cell of lithium ion Well, maybe I won't pick that. I want to be surface mount And see what they've got. So let's only go for active parts because I don't want to deal with Um, next up. We've got a couple options, you know, basically lithium ion lithium cobalt oxide, you know, lyco lithium ion polymer Maybe multi chemistry. I think Whatever, it's fine. I think, you know, lithium ion is covers everything, but still Next for the interface. So I actually had to look up. What is hdq? Um and sdq. So it turns out those are basically one wire So I don't want those so I want I squared C and hdq I squared C Um, I don't want one wire that I looked At the ones that are dash and those are actually Like battery protection monitors like they don't have any interface at all They just like turn on and off the connectivity to protect the cell I want something that's it's really a model like Not like a monitor to like care for but a monitor so I can like query it Okay, so It pairs it down a lot. So you can see like this actually the lc 709 204 is Clearly the next generation, but again I don't like the bgas and I don't like the bgas with the pads in the middle Like I do stuff with because I don't want to Have to route around. Um, I don't want to have to get like a four four world board And I don't want to do a four layer board lazy Let me let me be lazy Um, okay, so given that, uh, there's actually quite a few options So first up I'm going to do, you know, the pricing is really important to me Like there's just no way I'm going to make a board with a three dollar chip on it It's basically adds like 10 bucks worth of cost. It has to be like around it has to be less than two dollars So let's see what is available. I also want stuff. That's only normally stocking I don't want if it's not something it's okay if it's not in stock right now But if it's something they usually they don't stock at all. I don't want to You know, I don't want a special order or something. I'm never going to get So actually there's a couple of options, including of course that LC 709 So this is by price so you can see, you know, this one's actually quite interesting. So this is the F F FG 30 105. So this was interesting. It's actually You know, I mentioned I don't want a better protection cell. I want something to tell me like the state of charge And this is actually kind of both Um, it has a unique identifier It has iSquared C on it, but it's also meant to possibly Control and signal of protection. I see It doesn't have a sense resistor Um, but one thing that is a little annoying about not that I have a I don't have a big problem with this chip But a little bit of a thing is it only really is an adc Like it doesn't really It doesn't have An alert output I'm sorry, it has a chip enabled so it only it's like there's one output, but that just is like Something terrible went wrong. Like you can't really like customize it very much And if you go down to, um, you know the register maps Hold on Beep beep beep beep beep Um, you can do pack you can read the pack temperature and the voltage temperature It says sell current but that actually doesn't work And like there's just user id like a batter id. So it's it's not really It's basically an iSquared C adc. That's extremely low power. It doesn't have any like monitoring or alerts or um state of charge calculator, so It's not a bad chip. I mean it's 50 cents, but it's actually kind of like not what um, I'm looking for So that was cool. I kind of skipped over these I mean I looked at The datasheet for these a lot of these were good, but again, it's like I really I didn't want a 0.4 millimeter bga if I could avoid it um Also, a lot of these required a sense resistor and again I kind of wanted to avoid that a sense resistor is of course Gotta get you the best Like coulomb counting you're going to be able to track the current going in and out but um It makes it a little tougher for people to Like if you've got a feather and you want to like monitor it online Or if you have an existing system and you don't want to get in between the battery Like if you don't if you want to tap onto the battery, but not get it in between Um, this is more complicated. That said, you know the the bq series has some good options and One thing to check is um Sometimes not in this case, but sometimes if you're lucky The middle pin, which in this case is b2 can connect to another pin. So again, it doesn't have to go out but unfortunately in this case, um It is uh It it is a ground pin and they're expecting I think to have like a plug to be on You know inside to to get to the ground pat that ground plane underneath Which I don't want to do so i'm going to skip those and then there's a whole family of them um The next ones that seemed okay were uh like this one It's not in stock right now this ti series, but um It wasn't a package that wasn't it's a vison. So at least you can solder to it, you know without wanting to die Um, doesn't look too bad, but again, it you know doesn't require a sensor resistor. So, you know, not not terrible But um something to keep in mind But I would you know look at that because it is inexpensive and then um There is uh another one from maxim This is a fuel gauge. This one does also need r sense and it has it requires an r sense against the ground It's a low side sensing which um really drives me nuts because I really don't like Having grounds that are different like I don't mind if the Power voltage, you know can dip a little bit, but I really dislike it when my grounds are moving So unfortunately this one is kind of a no-go Um, so like as I scroll down, there's more of that bq series and that's when I basically bumped into um the max 17 048 because this kind of is very similar to the lc 709 203 No sense resistor run directly off the battery. It has an alert has i-squared-c. It's pretty simple um You know and I got the driver working, you know in a couple hours in circuit python And another nice thing about it, which I thought was nice, uh Is that the you know, it runs off of a battery, which is expected to be 2.5 to 4.5 volts But the data pins can be up to five So, you know if you're using this with something like an arduino uno Or some other five volt microcontroller you can send i-squared-c data Five volts even if the battery is at like 3.3 like it's it's protected. So um I ended up going with this chip, but I did want to show one one more option because I saw this weird Chip so I was like well like let's look at this It was the ltc um This ltc wasn't too bad Also required a sensor resistor, but there was another one if I can remember it was Hold on I have it in my uh Actually, I don't So let me actually look up analog Devices maximum Let's see if I can find it Was it this one? No, sorry not analog. It was um Linear this one. Oh bummer. I can't find it. There was one interesting um chip maybe we'll highlight this that uh linear tech came out with And um, what's neat about it is it actually the Sensor resistor wasn't inside the package itself Um, and it could like it did the coolant counting But didn't need an external resistor like it did high side sensing All on zone I can't find it now, but um If I do later we'll post about it, but The problem is that that even though I like that that resistor that it was a high side sensor resistor on the inside Um, it had 100 milliamp current um output max. So in the end, um, what I ended up going with was the um max 17 o 46 Benefit also was there's 10 000 stock. So, you know, I'm I'm ordering basically a reel of these and I've got the breakout We're ready to go now But these have been actually in stock for quite a bit like the maximum has done a really good job of keeping them Available for digickey. So I'm feeling pretty confident that this is not going to be discontinued um In the next two weeks if I'm picking a replacement I want to try to pick something that's good for like three years at least summarize nicely in the chat Sounds like this week's great search lesson is at a time finding a suitable replacement take some diving into the details of the Dishy to recommendation Recommend configuration That's right, especially with battery monitors are all a little different Like you saw some are high sides and one low side some of the sensors are some don't some are Some they have I squared C but check the register map. Does it really give you what you need? um But yeah, this one this one's a good one I'll probably end up also looking at a high side, you know, a current sensing one um as as a backup alternative because These the the model gauge ones like these where they try to model the state of charge based on voltage and Voltage change are really funky, but they're they're a little unusual. They're weird. All right. Well scur has a good pun It's a real experience r e l and then immediately I said, oh, we should do a new show the real world where um We put five engineers in the house and we don't give them parts. Let's see what happens They have to they have to fight over the last, uh, you know Tube of at mega three. I'm not here to make friends. I'm here to do engineering Sounds like random hall. Okay naked and afraid of not getting parts Okay, that's this week's Great search. Thanks