 Alright, thank you so much DigiKey. This week's IonMPI is MicrochipLady. What is IonMPI this week? Okay, this week's IonMPI is from Microchip. Weirdly coincidentally, I actually, this showed up on the DigiKey.com slash new featured product list and I had a breakout board designed for this. So now that it's back in stock, I was like, oh, I can talk about this chip and also I know a lot about it because I already wrote a library and come for it. So this week we're talking about the Microchip MCP3421. It is an ADC, a single channel differential ADC with up to 18 bits of resolution, which is a lot of bits. You know, most ADCs that people have had microcontrollers are 8 bit, 10 bit, 12, maybe 14 if you're lucky. So 18 is quite a lot. 18 basically means you can start doing very small measurements on the microvolt scale. What I like about this ADC is, you know, it's straightforward. It's got a single channel differential. It's got the 18 bit. It uses I squared C. So it's very easy to interface. It's got a couple settings. So you can change 12, 14, 16 bit resolution, which also will change the data rate because it uses a sigma delta and long input. It's got a built-in voltage reference. So you don't have to have like an external, you know, A ref generator, add to your bill of materials and size. It's all built in. It's got a built-in oscillator. It's got built in gain. So up to eight times gain. And it's like really simple to use. It's just like a SOT 236. So let's take a look at it. So you see at the bottom left this this chip, by the way, you know, is I squared C and it has a fixed address. You can see there's no address pin. But there's variants that come, you know, different variant ordering codes that come with different addresses. I think I have a diagram later of that. Differential input powered from 2.7 to 5.5 volts. The internal reference is 2.048 volts. So your signal has to be within that range and it's differential. But as long as like both the positive and negative are between ground and 2 volts, you'll be able to read the differential signal in. So it's a sine data. And then just I squared C for configuring and reading back. Just uses Delta Sigma. So, you know, one of the things about Delta Sigma is you can basically add as many states stages as you want. So, you know, you can do eight bit, which is fairly fast. Then, you know, every bit you add doubles the amount of time it takes because you have another stage. So the trade off with having Delta Sigma is it's not very fast. This I think when you go to 18 bits, it's like three, four, maybe five samples per second. So this isn't when you're wanting to like measure, you know, potentiometer or an analog like audio signal. This is good for sensors like pressure sensors, strain gauges, thermocouples, anything that needs high precision, but you don't need very fast reading. Okay. So here you go. So the at 18 bits, you're going to get, you know, 16 microvolts per LSB. But then on top of that, you can have a gain inside. There's a gramable gain of up to eight. But still, you know, even when you multiply by eight, remember, it has to be less than 2.48 volts. And the output, which it gives you will be between negative, you know, whatever number of bits divided by two to positive. So you can connect the negative pin to ground if you want, if you have a single ended output. But, you know, again, it's designed for stuff like thermocouples and we stone bridges where you want differential input. And here's an example of some wiring. So we stone bridges are used, you know, again, pressure sensors, strain gauges, you know, other, I mean, there's a couple of GSRs, I think, also use we stone bridges, wherever you have to measure a small, small change in resistance. This is kind of what it's set up to do. And, you know, if you need, I think for some strain gauges, you know, if the if the change is very, very small, you might want to add a op amp at the bottom, you can see there the MCP6V01, I think it's an auto zeroing precision op amp. So that will be good if you have a measurement that's, you know, you're going to go below that 16 microvolts per LSB measurement limit. So the demo that I've got is, you know, because I looked at the issue, it's like, you know, you can just hook up a thermocouple directly, you don't need anything else. They show an MCP9800, but that's just because you want to get the ambient temperature to do, you know, compare against. So you because the thermocouple has the change in temperature from ambient. So you use the ambient to then calculate what the absolute temperature is. You're really overhead over the demo now. So I've got, so this is the, okay, so this is the breakup board here that I designed. So you can see the chip over here. And I just have it connected up to, you know, I've got like capacitors, pull up resistors, a little ferrite bead. And then this is the differential input. And then I've wired the differential input here to a k-type thermocouple. And then you can see this is the ADC reading. I'm just picking this up. And then when I breathe on it gets warmer and you can see the ADC fixing up, even only a couple degrees. The micro voltage can be, you know, with eight times gain and 18-bit resolution. It's good enough. You can actually measure a thermocouple and get a couple degrees precision out of it. Directly no pre-amplifier, no signal conditioning at all. So a very simple and easy to wire up analog digital converter. Okay, so let's go back. We were just showing off the thermocouple. Can you go back? Yeah, okay. So then, yeah, we're gonna do the next one. Sorry. So this is the PCB design. This is just an image. Again, the bill of materials is small. You know, I just have a bulk capacitor, 0.1 micro farad capacitor, a ferrite, and then a couple of 10K pull-ups. But honestly, probably most of these items you're already going to have on your board. So really, you know, all you end up needing is just that Saat 236. Because again, it can run from 2.7 to 5 volts. You don't even need a regulator for it. And then to write a library, you know, I just wanted to write one very quickly. I just loaded up the datasheet into chat tpt4 and microchip. Data sheets are so good that it was like, yeah, no problem. Here's the library. And as always, we... The link is into the chat, isn't it? We use these tools. We link, disclose, we put it in any code. We link to the actual chat that you can see where Ladyata typed and stuff. And a lot of the code is trained on Ladyata stuff, not all of it for things like this. So I think we're encouraging others to do that. And I wanted to mention we... Can you do that? Yeah. So, you know, what I like about microchip is the datasheets are so good that they're very easy to parse by a chatbot. And it was able to kind of pipe out the library. And then, you know, there's a couple typos and so, but I fixed it up and published it on GitHub. So if you want to get started with this chip really quickly, I have a full Arduino library that sets the gain and the resolution and displays it on this TFT or displays it in the serial port and also calculates your samples per second. And then, yes, if you want to... The default iSquared C address is 0x68. But if you want, there are a couple different variants and DigiKey does stock them. So if you want multiple ones on one iSquared C port or either use of an address conflict, check the ordering code because, you know, they're not going to be compatible. On the other hand, if you want to make sure that your system doesn't... Your design doesn't get affected by part shortages, just make sure that your code is looking for any of the eight addresses that you could get depending on which version you place on your PCB. And kind of interesting. Dark mode. Not only is it in stock, but DigiKey looks like they rolled out dark mode. Dark mode. Maybe they just did it for you, but everyone should check and see. Love it. I mean, you know what? I'm going to take it. So in dark mode, in stock, all the options are available. This chip is about $2. I found it very easy to get started with. Order it and you can have it in your hand by tomorrow. All right. And then there's a short video that Microchip has. We're going to just play a little snippet from it and then we'll see you on the other side. Chip's MCP3421 weight scale demo board was designed to demonstrate the MCP3421 ADC's performance in such an application. It uses the PIC18F4550 microcontroller for data processing and USB communication with APC. This board also demonstrates the differences in system performance by adjusting the parameters of the sensor signal conditioning circuits by means of Microchip's MCP6V07 AutoZero'd operational amplifier. The MCP3421 Delta Sigma ADC can detect an input signal level as low as 2 microvolts. When measuring such a low input signal level, a low noise operational amplifier is used. The MCP6V07 AutoZero'd operational amplifier has input offset voltage correction for very low offset and offset drift, which makes it ideal for boosting small signal levels. Various signal conditioning schemes can be tested, providing the user an idea of how best to achieve the design requirements. Additionally, you can connect your own load cell for evaluation. An LCD displays the user selection option, ADC output code and weight. Buttons beside the LCD allows user control. The S4 button is used for offset calibration. S3 adjusts the signal conditioning gain settings. S2 is used to change the information displayed on the LCD. And S5 resets the demo. A LabView graphical user interface allows gain calibration, shows weight, standard deviation, ADC code and other data