 This week's IonMPI is Maxim and a lot of devices, Lady Iida. What is your new product introduction? I forgot your bi-digit key. This week? All right. This week's IonMPI is the Max 31329, a low-current real-time clock chip, as shown here. It's a 10-pin TDFN chip, so it's pretty easy to use in your surface mount project. It's a 5x5mm chip, and it's got a lot of cool things going on in it. I'm always looking at real-time clocks, and so there's a bunch of stuff in this MPI that caught my eye. This is the chip, so it was originally, I think, designed at Maxim, and then Maxim was recently acquired by ADI, and so that's why it's got Max and the part number ADI on the data sheet. So this is a real-time clock. A lot of people use these. You've got a product where power may be lost, but you still want to be able to keep time and do so in a very low-power way. Initially, this is what real-time clocks used to look like. They'd have a battery built-in, they have the chip built-in, and they have a crystal as well, and this was used on a computer or a motherboard, so that even when power was lost, that computer would keep time, which is great. This is what I didn't like about VCRs as a kid, is you lose power and it loses time as well. You should have had a real-time clock inside of them. I think nowadays, DVD players, they've had a real-time clock. It's a little bit more expensive, but basically lets the product keep time, again, when battery is low or power's out. So if you have a device that's off for a very, very long time, and the internal real-time clock battery also dies, that's when it's like, hey, I don't even, I think it's 1970 and it's noon. So this is like real-time clock the way we carry them and have a breakout for it. This is the DS1307, it's a classic real-time clock. So the chip itself is in the middle, that's the DS1307, and then the rectangular thing is the crystal. There's a 32 kilohertz crystal that's used to keep time, and then a battery. So the real-time clocks tend to use less than a microamp, which means that they can really sip a battery, even a small coin cell can last years or even a decade. So no matter what happens, no matter how long the product is depowered, it'll always know what time it is when it wakes up. So that's the old-style RTC, this is the Maxim 31329. So one thing that I thought was very cool about it is first off it's got the crystal built in to see the oscillator inside with a little X1, X2 kind of in the top middle. You know there's a there's a couple implications for it, but one is you don't have to pay for a separate crystal, which is usually 20 to 50 cents, and second you can get more accuracy, which we'll talk about because it can be tuned with the loading capacitors. Usually the loading capacitors are specified for the crystal, but you don't really know what it's going to be until you know there's always a little bit of variation, but with this it's internal. But it's very similar to a lot of RTCs, it runs off of I squared C. There's an optional clock input, you can see D in, which is quite nice. There's two interrupt outputs into A and B, clock out, clock in. Sorry, data in is for, it's not the clock in, data in is for interrupt support into the device so I could wake it up. And then VBAT is the secondary power. So some RTCs don't have a secondary power supply, there's the main supply VCC, which is usually power or wall or 3.3 volts from the main system. And then VBAT is the secondary lower power supply for when power is cut out. Again some RTCs don't have two power pins, and they make you have to manage that on your own. I like that in this case it can auto-detect and switch over to the battery when main power is lost. So that's the first basic thing. Second off, it's again pretty small. It's not a big SOIC or a T-SOP, it's a nice TDFN chip. All the pins are used, it's very convenient, especially since the crystal is built in, only 5x5 millimeters. So two of the things that really I think feature quite well on this RTC. One is the battery management and the battery life. So this is a low power RTC, it uses 240 nanoamperes. And that is about half of what most RTCs use. I think the DS1307 I looked up and it's about 500 nanoamperes. So great, you know it'll last twice as long on the battery. There's also a trickle charger that can charge an external supercap, or if you have a rechargeable battery. I thought the supercap, especially since it uses half as much current, a supercapacitor which looks like this, it looks like a coin cell, but it's actually like a .07 or .2 farad capacitor. It's basically like a battery, but you can charge it very easily and discharge it. And by using the Maxim supercap calculator, you can see that even, you know, I think in this case a 2 millifarad supercap running at the 240 nanoamperes typical current will last you, I think it says like 60 or so hours. So, you know, you can, or you know, a couple days worth. So if you think that your power is not going to be out for more than a couple hours at a time, then you can use a supercap. It means you don't have to deal with the lithium battery, which is always like shipping management gets more complicated because you have to label it as containing a lithium battery. You can't recharge a lithium battery. The supercap, of course, it'll automatically recharge instantly the moment the main power gets turned back on. So I thought that was nice, you know, especially with the lower quiescent current, timekeeping current, it makes more sense. There's also, you know, the built in trickle charging circuit. You can see here how it's hooked up. You can select which resistor to trickle charge through. And they even put in the shocky diode. How handy is that? So it's very, very inclusive. Really, if you, all you need is a supercap on the VBAT pin and you're ready to go. The second nice thing about this is, oh, if you, well, we won't show it, but this is the DS3231. And this is the high, extremely accurate temperature compensated crystal real-time clock that we carry. And these are like, this is kind of the highest and most precise real-time clock you can get. Plus or minus 2 ppm for room temperature-ish. And this is what it looks like. It's really big. It's a big RTC. So definitely not like you could put it in a wearable or anything. It's a chonker. It's 16 SOIC. And it's got the crystal and then a temperature sensor to do a temperature compensation. Whereas what's nice about, yeah, what's nice about this, the Max 3139, sorry, I want to get the right part number and there's a lot of threes. Max 31329 is that if you see at the bottom below in benefits and features at the bottom, integrate crystal load capacitors 2 and 2 plus or minus 5 ppm. So compared to the DS3231, it's not going to be 2.5 or 3. It's going to be 5 ppm. So not as precise, you know, but given the fact that it isn't temperature compensated and the price is significantly better, like you have to pay quite a bit to get the temperature compensated RTCs, the internal crystal and the load capacitors that are tuned and trimmed at the factory mean that you're going to have much better clock accuracy than your typical RTC where you have an external crystal. Usually the crystals are plus minus 20 ppm. So you'll get like four times better accuracy. And also you don't have to purchase that component separately. So yeah, so you can also pick up in a val board. It looks like an Arduino shield compatible that also comes with a dev board, a maximum microcontroller dev board if you'd like, but you can remove that and just plug it in. Again, it's I squared C. So, you know, use wire or use whatever, you know, a lot of dev boards have Arduino pinouts on them. You just use I squared C, follow the register map and you can set the alarm, set the clock times, all the good stuff that you expect from an RTC, and also take advantage of the extremely small size, full integration, high accuracy and low power. Available Digi-Key and it's in stock. It's actually not in stock, but it will be in stock. I'll add it down past. Sorry, it's just so good I didn't want to pass it up. It's going to be in stock in a couple of weeks. The val board is in stock. This really is new, NFI. I know. This is so new you can't get it yet, but it's not like it's not like the other things that you can't get. This is coming this is actually going to come again. It's going to be in the stock in like I think two or three weeks. So I actually have some on order that I'm going to get on the horizon. Look, it's a chip shortage time, but I still want to celebrate these good chips. I think this one's worth waiting for. Okay. And that's I am here and PI soon.