Welcome to CuVoodoo the sorcery of copper
In this episode I will talk about
how to identify electronic components
Whenever you want to find out how an electronic board works,
you have to remember how they are made.
First there are all the electronic components,
which have different functions.
A connector, a micro-controller,
button switches, a crystal.
And then there is the printed circuit board.
The board allows you two things.
First, it's a rigid substrate,
where you can place all the components on.
And then there is a sheet of copper on top of it.
This is the light green which you can see.
And it allows you to connect all the components between each other.
Here we can see for example
From this micro-controller, these leads are connected to the copper here,
and then there is a trace going to this component,
which is a capacitor.
Just by visually looking at the copper traces,
which you can see,
you can know how the components are connected together.
On very simple boards, you only have one layer of copper.
And it's very easy too see where the connections are.
But on a bit more advanced boards, you have two layers.
One on the back, and one on the front.
And you can even interconnect the two layers.
For example lets look at this LED.
Here there is a connection to this round via.
What this via allows you, is to connect to the other side,
The connection is made here.
We can continue to trace along this path,
and then we have a via again here.
So we turn over.
And we can see this via connects to this micro-controller.
To this lead on this micro-controller.
So now we can see this can we can trace connections.
How we can find how the components are connected,
just by visually looking at the traces.
Some traces my be hidden behind chips.
But most of them you can see from the outside.
But there are even more complex boards, like this netbook motherboard.
Where here we have one layer in the front,
one layer on the back,
components on both sides,
but we also have layer in between these two layers.
So even if you can trace paths which we can visually see,
because of the light copper on one side and the other,
we have no idea how the copper paths are done,
and how the routing is done in between.
And even worse.
If you look here.
We have lots of very tiny vias.
And on the other side,
we don't have that many of these tiny vias.
So it means that the vias don't go from one side to the complete other side,
but they are micro-vias, or buried vias.
They just go from one layer to any other layer.
And then there is even more routing.
So this makes it quite complicated to visually route,
and find out how the components are connected from one to the other.
But in this case you can use the continuity mode of the multi-meter,
which is denoted by this audio symbol.
Just switch to it,
and here we have the audio symbol again.
And what happens is:
If you short the leads, there will be a beep.
♪ multi-meter beeping ♪
Now we can can which lead is connected to which lead,
so we can find out which component is connected to which component.
For example this lead,
is connected to this lead.
♪ multi-meter beeping ♪
So whenever you have exposed leads, like here or like here,
it's pretty easy to find out how the components are connected together.
There are some packages, or some chips,
where the connections are underneath.
Like here. We have tiny balls all over the chip.
And there you can not probe with the multi-meter.
But at least with normal chips, with exposed leads,
you can find out how they are connected to the other components.
Now that we know how the components are connected together,
we have to identify the components themselves.
And this is where the white marking are quite helpful.
This is the so-called silk-screen.
And this is where the board designer will put some textual information.
So these small text marking which you see,
are reference designators.
They usually start with at least one letter,
and end with a number.
For example here we have "C505".
"C" stand for capacitor.
So this is probably the 505th capacitor.
But you have also other markings,
reference designators.
For example here it starts with "D".
"D" denotes that this is a diode.
We have "R" for this component.
So this is a resistor.
"Q" stands for transistors.
Then we have "U" for micro-controllers, or integrated circuits.
We have "L" for inductors.
But there is no unique standard,
to name the different components.
It's up to you.
The one which I told you are the very commons ones,
like this one: "X" for crystal.
But when it get a bit more fancy,
you can use whatever you want.
And you will find different markings on different boards.
For example here we have "CN" for this connector.
Sometimes you will find "J".
Sometimes you will find "CON".
Sometimes you will find "P".
It's really up to the designer to use the reference designators they want.
There is a wiki page with a non-exhaustive list,
https://en.wikipedia.org/wiki/Reference_designator
which at least shows you the different kind of marking you could use.
You can also identify components based on their package.
For example this electric component.
It has two terminals.
It is black.
It is flat.
This is a chip resistor.
They very often come in this package.
Here we have also two terminals.
The body is a bit thicker.
And it's brown.
The is a multi-layer ceramic capacitor.
This package with three leads is very common for transistors.
But it doesn't always have to be this way.
For example this one.
It's exactly the same package.
But this is not a transistor, this is a diode.
That's what the reference designator tells us.
And then you have these packages, where you have tons of leads.
This is a micro-controller, or a integrated circuit. But something more complicated.
And to find out what it is, we could use the top marking here.
But we'll come to that later.
Yet another way to identify components is based on their location,
and the components which are nearby.
For example on this chip.
We have next to it lots of small capacitors.
This is because when you have some kind of processing chip, and you are working with a signal,
you want to have very clear signals.
And this is why you put bypass capacitors next to the pins.
This chip itself, this is probably some kind of voltage regulator, or power management.
How do I know?
Well, if we flip the board, we see very big capacitors, very big inductors.
We have large traces.
So somewhere here there is some kind of power management or some voltage regulation done.
Since this chip is here, this might be doing it. But this is just a guess.
Now if we look at this chip.
There are not a lot of other components next to it,
except some connectors.
But again, if we flip it,
we see there is a card slot.
So this chip does some memory interface.
And it makes sense to put it next to the card slot,
because you want to connect all these pins,
to this chip.
So it wouldn't make sense to put this chip on the other side of the board,
because then you would have to route all the signals over the whole board up to this connector.
Here we have an Ethernet connector.
And because we want to protect the inside circuit form the outside world.
There could be some kind of shock and so on.
Generally when you have an Ethernet connector, next to it, or somewhere around, you have some Ethernet transformer.
And this is this component.
It's very recognizable by its package, but also because it's next to the connector itself.
When you tear apart products or when you design boards,
you will learn slowly where to put components next to each other.
And this is a lot of experience.
Like the packages themselves, how the components come in which package,
this have a lot to do with experience.
So just take apart products and do a lot of electronics by yourself, and you will find out.
For example also, this is a crystal oscillator.
So somewhere around here, there is some kind of micro-controller which uses this crystal oscillator as clock input.
Now lets come back to the top marking when we want to identify huge micro-controllers, or huge integrated circuits.
Lets have a look at this one.
On top you have the logo. The Big "A"
This is the logo of Atheros, the vendor of this chip.
Just under it you have even the name, Atheros.
The you have the part number: 8132M-AL1E.
And this tells us what kind of chip it is, and what it does.
Just under it you have another number: BE9815B1.
I don't really know what this is.
It could mean several things.
It could tell us about the options which are present on this chip.
It could be some kind of vendor internal information, or internal reference.
It could give some information about the manufacturing, and so on …
Below it, you have 0937.
This tells us that this chip has been produced in the 37th week of 2009.
It's the date-code of the chip.
And then in the end it tells us where it has been produced.
In this case the chip has been produced in Taiwan.
So, this is quite an exemplary top marking,
where you really have all the information.
If you look at this one,
we don't have the vendor name anymore.
But the vendor logo includes the name.
So this one is from Intel.
It doesn't have to be always this way.
Now on his chip,
let me make it visible,
we don't have the vendor name which is in the vendor logo.
We just have an "i" on the left.
And this "i", this vendor logo, is actually from Intel also.
This is well known.
This chip, on the other side, is not well known.
We have have the logo, no vendor name,
and then we have the part number: SLG8SP513V.
And if we look for it,
if we try to find more information,
for example in Google, or in any search engine,
we will find that this chip,
the vendor for this chip is Silego.
And very often, the beginning of the part name,
or the part number,
includes some kind of reference to the vendor.
So "SLG" is very similar to Silego.
But it doesn't always have to be this way.
If we look at this chip.
We also …
There is little marking.
This is probably the date-code,
meaning it has been produced in the 45th week of 2009.
Again 2009 like we found it on the other chip.
It might be the same one.
We don't have the vendor name.
We just have this logo. I don't know this logo.
Then we have the part number: LF-H84P-1.
And this, if we Google for it again,
we will find that the vendor is LANkom.
And the logo matches to LANkom.
There are even some dedicated search engines,
to find datasheets about the chips,
like octopart(.com),
or alldatasheets.com.
But actually I find Google to be the best search engine.
So you just put the part number,
which you can read from the top markings.
And if you don't find the exact result immediatly,
you can still put a bit of information.
We know that this component is a LAN Ethernet transformer.
And generally you'll find enough information.
In the answers we see there is enough information to confirm our guess.
Another useful aspect with Google,
is that when you put the component number,
you will have images corresponding to it.
And here we can see that the Silego chip, SLG chip, which we found,
corresponds to what we have.
We can even have a detailed look at the images.
And here we see a lot of images of the chip.
And actually it corresponds.
So it has the same package: TQFP,
with the same number of pins.
It has the same logo.
And almost the same marking.
So this helps us to really identify and to be sure it's our own component.
And if you don't have enough information, the vendor name is quite useful.
but if you have only the logo an not the vendor name itself,
there are dedicated websites like elnec.com,
which has a list of logos,
and when you click on the logo,
you will which vendor it belongs to.
So this will help you when you do your search for the part.
And there is also the second site:
classiccmp.org
which has another huge list of logos.
But as you can see here, these are small raster logos,
pixel logos, with not a high resolution.
So what I did is, I created my own page.
And here I put the logos of the chips
I find when I tear down some products
The different compared to the other,
it that, this is also only black and white,
because the markings are generally only white on the packages,
but also here it's not a raster graphic.
So no GIFs or no PNGs.
These are vectorized graphics.
You can zoom as mush as you want, and the quality just stays.
So what I do is …if find the …
Once I found who the vendor is,
I will try to find the logo, or something which looks similar to the logo,
and vectorize the image, so I can put it here.
And this is a small collection I did. and vectorize the image, so I can put it here.
And this is a small collection I did.
You can find it on https://iclogos.cuvoodoo.info
And you can also find the source code for it on https://git.cuvoodoo.info
And it's pretty simple. It's just one web page with link to all svg vector graphics.
And on some other electronic you will find this.
Here we have again a package with the top marking on it.
But here we have a giant epoxy blob.
We know that it's a micro-controller, or some kind of integrated circuit,
because there are a lot of paths going to it.
The difference is that they wanted so save some costs on the bill of material.
And instead on having the bare chip packaged in this kind of nice package,
with leads coming out,
and then you can solder the whole package on the PCB,
what they did is that they took the raw chip,
glued it on the PCB directly,
had some wire bonding between the chip and the paths,
which go everywhere,
and then you put a blob of epoxy
so to protect everything and to have it stick to the board.
And this allows allows them to save some cents,
because you don't have to package the raw chip in an external package.
They very frequently do that for custom chips.
For example for LCDs.
Here we have the LCD, so this is probably the LCD driver.
If we look at this LCD,
we also have three times a raw chip,
which have wire bonding to the traces,
and then you put a blob of epoxy on top of it, to protect it.