 Hi, I'm N.P.I. I'm N.P.I. brought to you by DigiKey and Ada Fruit. This week it's Texas Instruments Lady Ada. What is this week's I'm N.P.I.? OK, this week's I'm N.P.I. I actually was like excited about this because this is the DRV8411. It's a series of new motor driver chips from T.I. I love their driver chips for motors. It's available in both QFN and TESOP power package, PwP package right now. DigiKey only has the QFN in stock, but the TESOPs I'm assuming are coming soon. So this is the this is a series, the DRV8410, N11 and A motor drivers. These are small dual bridge motor drivers. There's two full H bridges. They're low voltage, so they're designed 1.6 volts to about 11 volts DC, and they can drive two brushed DC motors or one stepper motor bipolar or you can probably also drive a unipolar, but it's designed for bipolar usage. And it's a powerful driver that is drop in replaceable. You can see it's pink and compatible with the DRV8833, 8833C, which is lower power version, as well as a couple other similar chips, the 8847 and the ones in the family, the DRV8 410 and A411 they've got really low on resistance of only 400 milli ohms. They've got, again, low power, but wide supply range 1.5 to 11 volts. You can use logic levels down to 1.8. So you've got something running on two AA batteries. It'll work fine up to four amps peak, which is quite a bit, although we'll chat about some of the constraints of doing that. And particularly I like this because this is pin compatible with the DRV8833, which we have a breakout for. It's a very popular motor driver chip and we use it in a couple of different of our designs, not just the breakout, but also the cricket. Now, if you're wondering, what were we doing about 10, 10, about one year ago, well, May 26, 2022, we had a post for the chip shortage. We did a series on this video show called chip shortage, where we basically begged for chips because we couldn't get them. And one of the chips I really wanted was the DRV8833. We did eventually get them. I don't know whether it's because we did this video asking very much if we could get an allocation. Yeah, there is someone, I think it was a hacker newser and they're influencers, we're not influencers, they're influencers begging for chips online. That's right, we did. We will do anything to get chips we could get all components. They were half right, we were begging for chips, but I don't think we influenced much. Okay, well, it's a very funny video. You can go back and watch it. We did those almost every week. So the DRV8833, which is here, is shown our breakout board. You can see it's driving a bipolar stepper motor, four pins, and again, you can also drive two DC motors. I like that it's just like a general purpose, kind of use it for anything motor driver, which I like. A lot of motor drivers are like only steppers or only bipolar or only unipolar or only one H-bridge, but this is like, you drop this in, it can do a lot and it's inexpensive, it's only about a dollar. So the DRV8844, the DRV8411 in the 8410 is kind of the next generation. So this shows you the TI, this is their portfolio, as the RDS on the resistance of the built-in H-bridge goes down, you can do higher peak current, you have less power dissipation issues, more power is going from your power supply to the motor. So you can see the 8411, the big upgrade from the 8847 and 8833 is much lower voltage support, so you can go down below two volts and much higher peak current. The 8847 can go higher voltage, but if you don't need to go above 11, then these chips will do quite a good job for you. They're very simple. Again, unlike some stepper motor drivers, you control the individual H-bridge inputs, you get four inputs that you will PWM, and so if you wanted to do microstepping, you would actually PWM them to microstepping. If you're just doing half or full steps, you can just GPIO toggle the pins up and down. There's false information, so you know if you reach the current limiting and you can also put into sleep mode. There's also the AI-SEN and BSEN resistors, you can see those on the side, we'll talk about those, those are the current limiting. Basically, you've got brushed motors, two of them, Pop-A-Mon, step motor, Pop-A-Mon, good to go, and this is just a simplified version. It does the current regulation and protection for you. Of course, it's got the built-in flyback dyad, so it's very easy to use, you just power it, give it a couple of passive components and you're ready to rock. So there's three variations of this device, the 8410, 8411, 8411A. The 8410 is the most similar to the DRV8833 in current limitations and it's also pin-to-pin compatible, which I really like, you can just drop this in place. The 8411A is kind of interesting in which it updates from using external feedback resistances to using a current mirror, which we'll talk about in a bit, which is quite nice. The 8411, 8411A, basically basically, do you need pin-to-pin compatibility with the old chips, use the 8411? If you don't need exact drop-in compatibility, I recommend going for the 8411A, which is the MPI I'm actually picking, because again, you can reduce your board, build material footprint by using the current mirror capabilities. Also, if you need a really big motor, it does have parallel support. You tie A and B inputs together and then you tie the A and B outputs together so you can have a very powerful output for a single motor. Obviously not for a stepper motor, just for one brushed motor. However, like we said, it's got four amps output. You do have to figure out what is the power dissipation. You have to think about it, especially when you're dealing with four amps peak. If you're doing four amps just once in a while for a second or two, just to turn a motor to move something, maybe you're good to go. But if you're actually turning it on for a significant amount of time, you'll have to calculate your power dissipation. And since these are surface mount chips, not through a hole where it's really easy to attach, if it's a TO220, you can easily attach a heat sink. Heat sinking is not as easy. You could heat sink with the copper ground plate on your circuit board. We'll chat about that in a second. You might have to use also a little miniature heat sink or forced air to get air around it to remove the heat from the chip. You know, looking at the PWP TESOP versus the QFN, they have very similar resistances, but the QFN is gonna be a little bit better just because it's got, sorry, it's gonna be a little bit worse because it's smaller. The TESOP has a nice big heat sinking pad on the bottom. You will have to of course connect that to your gigantic ground plate dissipation and then calculate exactly how big of a plane you need. Don't forget to add plenty of vias underneath that thermal pad. It's not optional. Usually that's a mechanical pad. In this case, it's a heat sinking pad. They do have a lot of graphs in the datasheet to check out. You basically, it looks like you really wanna have two ounce copper. You can get away with two layer. Well, the four layer will improve, but two ounce copper on the outer layers will improve your heat sinking. Again, you're only using the motor here and there. Maybe you can get away with it, but the moment you're turning it on for more than 10, 20 seconds or more than 50% duty cycle, you'll have to think about this. There's also micro heat sinks. The TESOP, I think you can use some thermal paste, put this on, will it work? There's no heat sinking. The ambient heat sinks at the top is not gonna be nearly as good as the bottom. So what you might wanna do is actually have the heat sink on the back of the PCB. You expose the ground plane, expose the copper. You have it coated with hassle or ENIG, but still it's open and then you can attach the heat sink there. So you heat sink through the bottom, not through the top of the chip. So the A version, which I mentioned, the 8411A does away with this annoyance. So normally you have these big power resistors in there using, they're the current limiting. So you put them on so you can limit the amount of current. If you don't need four amps, you don't want to accidentally pull four amps if the motor stalls or shorts, you put these resistors in and they are actually in line with the age bridge. So you have to connect them to ground for the current to go through the motor and then through these resistors. However, because they're dissipating, they have to pull that full one, two, or four amps through them. They need to be really big to handle the heat dissipation because they have a 0.2 volt drop through them. And that's a little bit annoying because you can see they're quite big and you do have to think about the thermal ramifications of having these current sensor resistors that have quite a bit of current through them. And also they're just kind of chunky and expensive. So the A version of this chip does away with that and said there's a current mirror inside. And so there's a transistor inside that's going to do the dissipation for you. Hopefully there's even a multiplier maybe so you don't have that 0.2 volt drop. And in exchange on the output you've got what is called a prop I and B prop I, the maybe propagated current limit or current mirror limiting, I don't know. You still need resistors, but they don't need to dissipate the power. They're not in the power path. So you'll still need 0.2 resistors. They can be 0.603 or 0.402 really helps reduce the amount of board space you need. And of course, you can use that more for your heat sinking grand plan. How long did you get? They're in stock, 5,000 of each, the A and non-A QFN type. I'm definitely going to pick some up and do a breakout board. You can see the price thing over here under a buck. So they're price compatible with the DRV8833, but many improvements. Definitely recommend people check these out and maybe transition your designs. If you're doing revision, this could be a long-term solution. And that's our NPI. N-P-I-O-N-E-P-I.