EEVblog 1475 - What's This SMD Part? 

Another thing to be careful with if you're going to "drop in" a regulator without knowing what the original part was: the enable may be either Active Low, or Active High.

Running a feedback line under the inductor would be a terrible layout decision as it's a sensitive node that needs to be kept well away from the noisy switching output

I would definitely buy a giant EEVblog poster with all the SMD packages...

its a sad industry when you cant identify a part by what's written on the chip.

I would be inclined to get the connections figured out from the switching regulator to figure out where it is going (probably the big IC), and then get the data sheet for the IC and find out what the input voltage should be.

18:28 actually, this is not a filter cap, it is a feedback-forward cap which allows to adjust/improve the phase margin of the regulator by compensating the low pass behavior of the feedback path.

You should definitely do some more random dives like this on a variety of different cases, I think it's good to step people through your reverse engineering process with limited information.

Back to the roots! Thank you Dave! That´s where we all came from, watching your brilliance in analyzing I´m so happy

Mostl likely this is AAT1141 made by Analogic Tech (Fast Transient 600mA Step-Down Converter) pin out is quite general like the ones mentioned in the video but the marking matches AAT1141

What a wonderful public service you do for us young players in the design community!!!!

After all these years, your videos are among the tiny few here on this website where I still learn stuff.

when searching open google for very specific things, do not forget to add "quote marks" around your search to force it to search that SPECIFIC term, it didnt help me find this part directly but it did bring me onto onsemi

So much of engineering is just knowing how to read and understand technical data

I wish people would take wider shots when they ask stuff like this. The context clues about what it's connected to are very helpful.

21:00 The internal reference voltage for adjustable regulators **is** generally visible in parametric search -- as the minimum value in the Output Voltage Range. Because, after all, R2 = 0, R1 = open leads to Vout = Vref. You might not want to bet your kids on the parametric value being correct, but it's hugely helpful as a first filtering pass at least.

Here's a workaround for the small cursor capture: 1) disable cursor capture in OBS/XSplit 2) open the Windows Magnifier (the accessibility tool) and just have it zoomed out at 100%. Just keep it open in the background. This will cause Windows to render the cursor differently, straight to the screen/desktop texture.

Thanks for the logical and thorough examination Dave.

Nisshinbo is the successor of New Japan Radio and Ricoh Electronic Devices.

There are some awesome TI SOT23-5 switching regulators that can go up to 5A. They get quite toasty at 5A (but they still work fine at 25 degrees ambient), so i use them to around 2-3A and they stay quite cool at that kind of load. They do this by having a really interesting bonding technology that is done using the pin frames, and not just the thine bonding wires. That way then can dissipate a lot more heat than usual SOT23-5.

Good job, Dave! So many beginners would be lost and so few RU-vid videos address this.

He figured out more in a minute than I could ever do after hours of googling

Yes ! Great video.. Keep making more like this if you can. This helps a big part of the community that is new to electronics. Thank you !!

16:30 Great detective work and I learned to figure out unknown chips better given this example.

That was very helpful! Lots of new information learned. Thank you!

Thanks for another amazing video. As an automotive electronics design engineer this helps me to understand how to approach and identify components while benchmarking a design. One more input I'd like to give since this is a automotive application pcb. We could trim the list of components of required by filtering it by AEC Q qualified components and remove them commercial grade components. Thanks again....

Also because it's a recorder and not incorporated in the car, the only failure mode they have to care about is not shorting the busses / create problems when it monitors, so it could just be an obscure Chinese jobby because they just don't care. These don't have to be AEC-100 / 101.

Great analysis with a small picture of unknown circuit

This is a nice deep-dive into component identification. Good video!

Great Content. I imagine it's incredibly hard writing 30 minutes of component level electronics yet you always pull it off.

Thank you Dave. I've been waiting for a new video to watch. Nothing lately has taken my fancy, in regards to my Subscriptions. So Cheers Sheila 😉😁

Great video! I learned so much just in this one video!

I guessed it was a voltage regulator but it's absolutely insane you figured so much out about the circuit just from that one image.

@27:35 I'd assume the PH stands for PHASE, it's much more common notation for multi-phase VRMs rather than a simple buck regulator like this

you don't know how helpful this video was! always wanted to find a good source for this issue! awsome! thanks a lot! I always assumed those characters mean everything and you must be able to find the part from that characters. always thought my lack of knowledge was the culprit and there must be a website with those answers for finding parts! but now, knowing it's not always a straightforward path, I dig deeper. also do not forget the EEVblog's hivemind either.

It seems strange to me that the industry doesn’t supply an accurate reference for those small SMT package markings. That would save a lot of time and could be kept up to date by the manufacturers.

PH is probably Phase, they probably seller multiphase switching chips with PH1 - PHn pins.

Hey, thanks for a load of useful tips for SMT reverse engineering!

Good subject and content. Thank you.

Sometimes they tell you the marking code in the order section of the data sheet. So if you find a part that could be the part you are searching for (expected pinout, measured values = spec values) then (if you are very lucky of course) check if the data sheet tells you something about the marking in the order section and compare.

I love these kinds of videos!

The next line of investigation is to determine the voltage at the feedback pin. If you have another board that's working, or you know the output voltage for these type of cards, or you know the working voltage for one of the the other chips onboard, you have the output voltage. Then it's just a matter of measuring the resistors in the divider network. For example, if you have 200K and 100K and you know the output voltage should be 1.8V, then you know the reference voltage is 0.6V. That allows you narrow your search to parts that have an adjustable range from 0.6V upwards. You actually _do_ have the reference voltage in your parametric search: it's the minimum value for the adjustable output.

Filtering chip selection for specific reference voltages can be done by filtering minimum Vout because minimum Vout is in most cases limited by reference voltage.

When I see a couple different chips with most things looking the same I like to actually look at the die footprint in the datasheet to see if one is essentially just a clone of the other.

With the current information about the possible regulator, the next move is to check if that output transistor is shorted or open. A short case there is more damage down the output. Otherwise, what is the load, and see if an alternative regulator approach is feasible.

Excellent Video...

thanks for the video 🙂

my initial thought was that it would be a 3 V / 1 A regulator considering the marking :D

Half-way around the world from you, Coilcraft is based right here in my hometown!

I have the most respect for your diverse knowledge of electronics-you remind me of Jim Williams (who I used to work beside at NSM and Linear Tech). I do not agree with your cavalier opinion regarding the replacement since the inductor value is heavily dependent on the switching regulator frequency and operating current level. Too low a frequency and the inductor could well saturate; too high a switching frequency and the inductor could not supply the output current. I do not consider myself an expert but have designed several current mode switching regulators at Linear Tech. Switching regulators have a very wide range of operating frequencies, from 50kHz to several Mhz, requiring very different inductive elements.

Would be awesome to see the end outcome of what part they used

8:20 in case you can reason in any way about the involved voltages and currents one can reduce the list even more

It is a nightmare when trying to identify SMD codes because there is no standard. There should have been a standard that they will be given either and alpha, number or a symbol to identify the manufacturer at the start of the marking. That would be a breakthrough because then we could search that manufacturer for the codes remaining to identify the part but I suspect this has been done deliberately to stop right to repair.

When googling part markings, be sure to include something like "IC marking" in your search. That'll weed out the ladies jeans websites ;-)

RU-vid keeps recommending me this video, on and on. Now I see what you mean, it's a blackhole.

17V seems low for automotive unless the abs max is a lot higher or you have very good input conditioning

This is so nice to watch and listen to. I am an absolute novice with a soldering station and a chinese solder sucker gun. I have spent many a days trolling the internet, looking for this exact style of component and circuit explanation without all of the textbook time. I think I have adhd when it comes to long, drawn out theories of each component rather than showing it in an actual circuit and how it is related to the other components. I have a recent model multi - function welder/plasma cutter that I have been trying to repair for months. Without the proper education in this field, I resorted to removal and test of suspected components, replacing questionable ones with exact replacements from digi key among other suppliers and still no proper function...will not start a strong enough arc. I work in the industrial/ commercial hvac trade and have been dealing with a lot of large control board issues from various equipment such as large variable frequency drives and chiller mother boards. I would love to get more involved, so I hope you make more videos like this. Maybe sometime I could even send you some pictures of these control boards. Thanks for what you do !

This last one also has a much lower switching frequency which would probably work better with the current inductor size

Blimey, a real Sherlock Holmes!

I guess the same logic could be extended to reversing a more complex part. Such as a chip that has had its numbers scraped off, for example. 😉🤓

Dave Holmes at work!

good one mate

My instant thought was switching voltage regulator, when I saw that 'C' logo in the corner.

I remember finding the exact part number used in a D-Link wifi camera(some 6000 series wifi camera with 3 regulators) longtime back. I accidentally broke the inductor while disassembling it out of curiosity. Had to replace it with a similar inductor from a dead NVidia graphics card.

Getting your feedback voltage after it has been filtered by the output capacitors is good practice/design, you should not get your feedback at the pad under the inductor. Then you get less noise on your feedback.

Some issues I have with the layout (Or if someone knows why, please tell me): - Why is the top GND pour so huge with so few vias (one)? This makes the feedback path very long and with a large area. - I'm fairly sure the inductor is the wrong way. By having the witching node connect to the inner turns, the outer will shield the high-frequency inner turns and drop a few dB in noise. - Why are the output capacitors so far apart? - Why is the output pour so huge without any vias? Patch antenna time with capacitive coupling from the switching node, lol. - Enable line under inductor, wtf??? - Why is the switching node the size of California? There is no need for thermal relief for an inductor that size. It will not tombstone because the thermal relief is the only reason I could see for *some* of the area. Ok, In done now! lol

Watching this video is like watching an expert doing their thing. Impressive, and ego destroying for the viewer.

LOL at Dave's google suggested/custom search results.

I have to go to sleep, Dave! Alright, mate, just one more video...

Date code on the big chip suggests the part is like 20 years old.

the difficulty opf identifying parts like these says it all about the wastefulness of the current repair vs replace balance, whether you're talking about swapping out a board rather than bothering with component level repair, or even worse, scrapping an entire product. these components aren't easier to identify because most of the time no one needs to identify them.

This process of finding a part to fit the circuit is going on a lot at the moment as designers need to find alternate parts for products where chips are discontinued without notice or become unobtanium

FT440AA from Fremont Micro Devices Ltd.

(still watching, so not sure if you find a good match) My initial gut reaction is that pin 6 is the VFB, with R5 being the low leg of the voltage divider. (it's heading off towards the output side of the inductor) Leaving Pin 1 to be the enable (or some other function). Running the feedback under the inductor would be a pretty bad layout in my opinion, not to mention it has access to the output plane right beside that small cap right above the inductor, so doesn't make much sense.

10:19 I know this isn't useful, but the Nissinbho RP504 actually has the correct pinout. You were looking at the pin numbering/descriptions for the DFN packages, if you look at the table for the SOT-23-5, you'll find they match the photo.

Was waiting for the plot twist, where it turns out that the IC is not in stock.

Sometimes in lower part of pdf u can find marking data

Also, given the inductor value of 22uH it's a rather "low" frequency part, 200~300kHz I'd say.

Some data sheets have a package marking section. Can be used to validate your assumption.

Coilcraft makes some good stuff.

One of the problems is that the marking on this chip is not a part number it is called a device code. It is unusual that it doesn't have any brand identifier on it.

You might be able to get large mouse pointer by changing the setting in the "old" mouse settings via "main.cpl"

I expect that this board is being supplied +5V or +3.3V for the CAN transceivers and this regulator is just generating the +1.8V rail for the processor. In that case the input voltage ranges of those parts you found are all fine.

If pin 1 was FB then it would be connect to the two partial "output" caps shown, so pin 1 must be "EN".

Many datasheets also give you the markings for easy elimination. The TPS56... is NOT the part.

logics!

Great video! it's a chance for an expert to follow a real world use case and for my benefit :)

awesome

EDIT: Wrong solution. The cursor problem is due to windows scaling feature. On large resolution monitors it's common to increase the size of everything by 25% - 100% in order to be able to have large resolutions without making everything seem small. This creates some issues in programs such as OBS which measure the scaled dimensions, while any window rendering might measure before the scaling. In order to "fix" this, you have to go to display settings in Windows or any other monitor settings in linux and set scaling to 100%. It will be small and look bad, but everything will be the correct reported size.

If this is a reading/dataloging device it may well run off 5 volts usb and not require 12 volts. The more you know the better your chances. Thanks again Dave.

In todays world, you’ll need to work for the manufacturer/designer of the board/device where you’ll have the bill of materials and won’t have to waste time trying to reverse engineer the circuit to figure out what the part is.

This reminds me of Bunnie Haung's monthly Name That Ware contest.

If it's a car ( probably also truck ) recorder you look at Vin max of 32V. At this pack you won't get a lot of options. Problem is... you don't know if there is preregulation somewhere. pppffff... Ooooops... you said that also. The part number is really obscure, some letters of the marking should be options and there should be a stable part that's easily searchable.

Be good to know if this suspect part had an output? And the state of the enable pin, these things usually fail violently…

FWIW Richtek use the two character part code followed by three character date code for their switching regs.

10:30 You're reading from the wrong table! That is for the 6 pin part.

forgot include inductance and pcb layout to search. IC is frequency dependent, and many pcb include this module layout direct from datasheet.

Oooh the joy of inductance, until I learned about inductance I designed a board with a pic that was so random in it's operation I chucked it in a box for 6 years. Then one day after learning more I thought ooo wonder if I still have that. Dragged it out and fixed the problem with a few drill holes and it worked. Inductance is just magic l didn't have the correct spell for. 58 and still baffles me that an antenna is a short but not a short in ac 🤪

You suggest having a poster of SMD shapes ... any suggestions on where to find a poster ... or even a website that lists them? I find it frustrating when a company lists a part's package with their own terminology, which I eventually find as being identical to, say, an SOIC-8

Vampirella cosplay is obviously the search result you need to click on

A trace is always an Inductor unless it is a capacitor.