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    [MUSIC PLAYING]

    Hello. My name is Frank De Stasi, and I am an applications engineer at Texas Instruments. And today, I'll be showing you how to achieve small solution size and easy EMI compliance with one of our latest Wide VIN Buck regulators, the LMR33630. So let's take a look at the package first, for this particular product.

    As you can see, it's a very small QFN, two millimeters by three millimeters. And in fact, it's smaller than the external components required for the entire regulator. So with a very tight layout, you can achieve a solution size of 15 millimeters by 16 millimeters.

    The other advantage of this particular package is it's what we call the flip chip design. And essentially, what we have here is the die is turned upside down and soldered directly onto the copper lead frame. So in that case, you don't have any bond wires. And therefore, there are no parasitics from the bond wires. So the noise generated by those parasitics is now eliminated. That helps you to improve your both conducted and radiated EMI noise performance.

    In addition, this package has wettable flanks and a small step side cut along the bottom of the lead frame. And what that allows is for a very large solder fillet to form, when the part is soldered down onto the PC board, and that allows you to very easily tell that the solder job has been done correctly. That's very important for many automotive type applications.

    Another important aspect of this particular regulator is the way the input and ground connections have been laid out. As you can see from the slide, there are two sets of VIN and ground connections, one on either side of the die. And that means that the input current flows, from both sides of the die, from the input into the device. And what happens is the magnetic fields from those currents tend to cancel out. That also helps to improve both conducted and radiated EMI.

    So let's take a look at what we'll be testing today. Today, we'll be looking at the conducted EMI radiation from our regulator. Conducted EMI is a measure of how much noise the regulator puts out into the input supply of the application.

    So the equipment that we'll need are an EMI receiver, an input power supply, of course the DUT, an LISN, and the load. Today, will be taking a look at a very typical automotive application-- 13.5 volts in, 5 volts out, 3 amps of load current, and a switching frequency of 2.1 megahertz.

    So if we go a little bit more into our equipment here, we can see on the shelf we have our input power supply. Next to that, on the other shelf, is the EMI receiver.

    Now, the EMI receiver has all of the specifications built into it for the CISPR 25 Class 5 type of testing that we'll be performing here today. And that means that the limit lines and all the frequency ranges are built in, so it will be very easy for us to tell if our device has passed the limits.

    So why don't we go into the chamber and take a look at the rest of the setup.

    Here we are in the EMI chamber with the rest of our setup. These two units comprise the LISN. The LISN separates out the noise from the DUT, and sends it to the EMI receiver, and bypasses the noise from the input supply. We have one in the negative input lead and one in the positive input lead.

    As you can also see, our DUT is separated exactly 200 millimeters away from the input to the LISN, which is part of the specification. And our load resistor is connected very close to the DUT, so any noise generated in that resistor will not be counted and included in the scan.

    So let's go back in the lab and run the scan.

    Here we are back in the lab, and we're ready to run the EMI scan. So I turn the power supply on-- 13.5 volts-- the EMI receiver will go ahead and run the scan over the proper frequency range, and we can see our results.

    When we combine both the low frequency and the high frequency measurements scans, we can easily see that this device easily passes a CISPR 25 Class B specification.

    So in summary, it's easy to achieve a small solution size, and easy EMI compliance, if you have the right package and the right layout. For more information, please visit ti.com, and thank you for watching.

    This video is part of a series