# Tag Info

## New answers tagged pcb

2

Trace thickness is the thickness of the copper layer. In the US you order that by "ounces", which really means ounces per square foot. If your calculator wants the thickness in mm or inches, look up the conversion. Just to complicate things, you can order different copper thicknesses. The typical thickness is 1 ounce, and it's common to get thicker ...

0

Since you are using through-hole components, I don't see the need for any of the via's that you have. Not that they will cause any issues, but I don't see why you have the NodeMCU connections on the bottom layer and the other modules on the top layer. I also see that you have SCL and SDA, so you have an I2C interface. Make sure that you have appropriate ...

1

The PCB looks fine. However, an advice on the track width, use something like this. The width size is decided based on properties like current, copper width, heat etc ....... https://www.4pcb.com/trace-width-calculator.html

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Follow the traces from each damaged pad and connect a wire between that pin and the other end of the trace. If it's a TRS jack (and not TRRS), the extra pin may just be for mounting (mechanical) and not need to connect anywhere electrically. Be aware that this PCB likely has a ground plane which means that any pad that's supposed to connect to ground may ...

3

It looks like a VESA Local bus, aka VL-bus.

1

Assuming what you want is a Polygon Pour (ground plane around the signals/ components)... The procedure is the following: Go into the "Polygon Manager" When you are in this dialog box you can then make "New Polygon from" And I usually like to create it from the board outline, which will create a polygon pour over all remaining space on the selected layer....

0

This was driving me slightly nuts for a min, and I had some projects that would be "modified" as soon as Altium opened it and others which would behave fine. I dug through the project parameters looking to see what was different. I found something that fixed this problem for me, hopefully it helps you too. If you go into your Project Options, go to the '...

4

Use a zero-ohm SMT resistor for the strap. The cost of the resistor is about as close to nothing as you can get (tenths of a penny, even on Digi-Key) and will be reliable. You call out which version by using a different bill of material (BOM) when you go to build the board. Using a solder bridge would not be reliable, and will not pass DFM analysis at the ...

1

One sure way to avoid any fees is to do this with something that is settable yourself, like an 0.1" jumper header. Another way is with a dip switch. It really depends on the manufacturer. Some might want to charge you more, some might not care. Ask them how much they charge for variants. I do this with 0603 resistors, because they are listed as ...

0

If I would run this amount of Amps over my PCB I would need a 110mm wide track to carry all the load. The complete location for it on my PCB is only around 100mm. Can I just use 2 planes to connect everything together or should I worry about a short circuit? If you were to locate all the supplies in the same place and fan out all the LED's from the ...

1

The main things to consider are the required spacing around any conductors carrying high voltage, and avoiding pointy shapes on high voltage lines. You can look at online calculators such as... http://www.creepage.com/ ...for estimated spacing between conductors. Also consider the dielectric thickness between layers on the PWB. For the design to be ...

3

This is due to how PCBs are built. Inner layers are etched in pairs to copper that is pre-laminated to both sides of a core. Outer layers are bare copper sheets that are etched when the whole PCB is already laminated. Thus 8 layer boards almost always have 3 cores and 4 prepreg layers because there are three pairs of inner layers. You can find videos in ...

3

I do ground on both layers, and use vias named Gnd to connect the top & bottom areas. 15, 20 mil clearane around pads where you will be hand soldering, makes life a little easier. 10 mil wide traces, clearance down to 10 or 8 mil if things are tight. Wider for power, current dependent. I don't see anything extreme there, 24 mil is likely plenty. No ...

3

You can pour Vdd on the top layer. The added capacitance will help decoupling. It's also slightly better usually to have Vdd on the top and GND on the bottom in case the bottom accidentally contacts something grounded. If you're doing pours it's a good idea to increase the clearance for the pours to something big like 0.02" (0.5mm) so as to improve ...

1

Most full-service pcb fabricators will have a CAM department. These engineers normally clip off silkscreen which falls on holes or solderable surfaces. If they don't do that, you might encounter 1) Ink in holes, that might create issues while fitting a part/pin. 2) Ink on solderable surface, which might result in bad solder joints. If it's just silkscreen ...

1

KiCad has no check for silkscreen overlapping exposed copper. But you can select "exclude pads from silkscreen" (formally known as "remove mask from silkscreen") during gerber export to ensure no silk is where it does not belong.

4

Land pattern recommendations are in the realm of established best practice, rather than definitive proofs. The "same size" recommendation for QFN pads is indeed considered best practice. I'm not sure why, but suspect it has to do with providing a precise locating effect as the solder melts. So the answer to which to use, typical (nominal) or maximum, is - ...

2

The answer here is common sense. If the logo is placed on some previously empty space and its presence does not require any component placement or routing change there is no harm in doing it. If you're already using ENIG, by all means open the solder mask and make the logo shinny. I doubt that the PCB fab house will charge you more for the extra gold used. ...

2

Nope, there really aren't much downsides, especially with solder mask openings. The solder mask is electrically quite insignificant. If you'd have the opening on an impedance controlled trace it would have slight effect, but you wouldn't have it there anyway, because it would be ugly. If you have ENIG finish on the board, there's added cost, because there ...

0

We do this in our designs so that we can save money by totally avoiding silkscreen printing. The text as such will be small, isolated from all other sections in the circuitry and doesn't create any trouble with EMI EMC. Ofcourse this wouldn't be placed some where close to a impedance matched tracks but rather in a place which is easy to read but without ...

1

I believe that this PCB has a multi function applications, and it depends on fitting or non fitting components on it. So regarding what you showed us in your picture there are some unfitting elements such as R125 and R126, who are responsible to enable the LED. So these test points are not for the customer service and are only necessary in the development ...

0

The white writing relates to the capacitors, resistors and information about the actual test points. The circular pads with white circles are test points for probes to multimeters, scopes or a bed of nails test fixture. So looking at this picture we can say that the top row of components are capacitors and only one is there cc06. The next row beginning with ...

1

There are two differences that I could think of that would be affected by thickness: Heat flow and thermal on power planes, additional material will thermally isolate planes, which may or may not affect your performance of the power planes of being able to dissipate heat or conduct heat. If you have components with high or dense power dissipation. ...

1

I call these "remote designators" and as said by the helpful person with the illustration, these are meant to mimic the relative placement and orientation of the components they designate. Outlining the groups and using corresponding lookup letters is used when the group of designators is not close enough to the components to clearly represent them.

2

So you need to measure the speed of a fast moving object. This requires that you measure its position and the time at that position twice and precisely. Or if you know the weight of the projectile you measure its energy and hence derive speed. Neither of these things can be done with a plastic projectile through an inductive sensor. Go back to the classic ...

22

sorry for the poor drawing. i hope you can trace them. I don't know the technical terminology for this. We do this whenever there is no space to place the reference designator at the same time it can't be dropped all together too. Then Reference designator will be grouped together but at some other point in the PCB where there is abundant space. Care will ...

4

The test points are not on top of each other. The grouping you've showed has four test points (corresponding to the four net names in the label area) and pads for seven components (corresponding to the seven component names in the label area), some of them unpopulated. The test points are all round and circled in the silkscreen. There doesn't seem to be any ...

5

These look like test points, which are pads, pins or hooks used to test connections (to be able to place a oscilloscope or logic analyzer probe). This way developers can test if a certain voltage or signal is present; but to do this you must know the meaning of that point (pad in this case). It seems the text right of it might give a clue about the meaning. ...

0

you can use these guidelines Guidelines or similar as a reference for a decent layout. On the right hand side of the GUI, you will find track width graphic.

6

they are pads which connect from front copper layer to bottom ground layer You've just described a via. Do you think the board house will accept this? If they're on the ball they won't accept it. They specify a hole size because below that their process won't reliably plate the holes. Do you want your thermal vias to be non-thermal holes? Or ...

3

No this is a bad idea. Two problems come to mind immediately. One of the first things I was taught about soldered connections is that you should not rely on the strength of the solder to hold it together, that connection is doing that. In addition soldering the wire creates a stiff area which can result in fatigue failures of the wire depending on the ...

1

You might be able to mount your smaller MCU on a castellated-via PCB as shown in the picture below. This requires that the pin-pitch on the original chip is not too small, so there is room for the plated holes. Alternatively you could make a pcb with the original chips' footprint on the bottom side and your new chip on the top side, but it will be much ...

3

The thing you're looking for is called an interposer. It's a small PCB that adapts one footprint to another. A number of companies specialize in them. Some links below... https://www.advanced.com/products/package-conversion-adapters/qfp-adapters http://www.isipkg.com/wp-content/uploads/2016/09/ISI-Obsolescence-Solutions.pdf http://www.proto-advantage.com/...

1

From AN1445 - Antenna desugn guide for MFRC52x, PN51x and PN53x Antenna Symmetry The symmetry in antenna design is absolutely necessary with respect to tuning and EMC behavior. Otherwise common mode currents are generated to parasitic capacitances from the antenna to ground. Theses currents can cause emissions that hurt EMV regulations It can be ...

2

If you really need to solder it, one way to do this would to get some thick copper sheet metal, like 0.02" or 0.04", and and have a machinist put a bend in the copper at the angle needed. Put some thick pads on the board and solder the copper on. The problem with this is you would need a lot of heat for the copper (with it's large thermal mass) which might ...

0

It looks to me like that is the ground return path for the loop. If you'll notice that on the other side of the board the last loop crosses over and the 3rd coil is actually the last coil before ground. I think the main reason this was done was purely asthetical, as the current through the loop would be the same. It could change the mutual inductance ...

0

Which approach is more effective? You can have both. Via in pad from the ground pads directly to the ground plane, and a ground area on the outer layer connected to the inner layer ground with stitching vias. Please note that I am a student and cannot manufacture PCBs with blind and buried vias. Blind and buried vias are a separate concern from via-in-...

3

A copper pour amongst a bunch of component traces is NOT the same as a ground plane. This is because the whole point of a ground plane is to provide currents the shortest, lowest inductance (smallest loop) possible path. This does not happen in a copper pour riddled with component pads and traces since the ground/return currents must take the long route ...

6

You want as solid ground plane as possible, so you should have the ground on bottom and preferably have no other traces there. For better copper balance you should also have the copper pours on the top layer to fill the empty spaces. If there isn't any better use for it, connecting the pours to the bottom ground plane with vias is a good choice. Though this ...

1

It appears that the Arrange Components Inside Area is buried within the Alignment Tools menu on the toolbar. I was not able to find a way to customize the toolbar to move the icon out of the submenu and onto the toolbar. As @asdfex does, I use the keyboard shortcuts more than buttons. Primarily because of this very reason: they change style and position ...

1

There was an icon for that? I never used it - I try to memorize the 2- or 3-letter shortcuts, which is even faster than clicking an icon because you don't have to move the mouse away from the PCB and the second hand is already on the keyboard. For arranging components within a rectangle that shortcut is T-O-L. (Easy to remember, because it is a "great" ...

3

Should I CE marks the PCB if: 1.I sell the entire product as a kit? 2.I sell only the exclusive parts, making available instructions to mount them with other components (not sold by me)? sell entire product If you want to sell the entire product, you should satisfy all applicable directives, one of them being the EMC directive(1). If product A is EMC ...

2

There are two things to consider here, ESD and wireless signal strength. For ESD, it can be good to have a metal chassis surrounding the device going to ground to prevent discharges from humans reaching the device. The problem is the antenna's signal strength could be reduced from having a ground plane around it (if the metal chassis is around the whole ...

5

The classic approach when dealing with RTD's is the Steinhart-Hart equation $\frac{1}{T} = a b\cdot ln(R) + c\cdot ln^2(R)$ This is a very accurate model of the characteristic change with respect to temperature. This however is quite "complex" to deal with in real-time (if accurate temperature is require). The $\beta model$ is a special/reduce ...

4

The beta model is just that -- a model. You will get different answers for beta when you use different temperature points to estimate beta. B25/80 is likely beta when calculated using data at 25 deg C and 80 deg C. All those betas are closer than 1%. If you need better, consider using a thermistor quantified with Steinhart-Hart coefficients.

0

You don't need to but it makes soldering easier. Inductance is what matters more for ESD than resistance so the dimensions aren't too big a concern. My last question is if the other pad of the TVS diode, which connects with the ESD source can be soldered easily(also shown in the pciture), do I still need to care about the GND pad? Huh?

2

You can use an optocoupler if the motor is small, otherwise, you can use the output of the optocoupler to turn on the motor driver. Here is the circuit of the optocoupler, notice the LED that turns on the transistor on the other side. Here is the circuit with the optocoupler substituting the LED: simulate this circuit – Schematic created using ...

2

C1 + C2: these are for "supply decoupling". Logic circuits like a microcontroller draw current from the (5V) supply in short peaks. This would cause the supply voltage to drop and become non-constant which affects all circuits. This can be solved by adding "supply decoupling capacitors" (sometimes called bypass capacitors) as these behave like a local ...

1

For the capacitors, see Bimpelrekkie's answer. Zener diodes D1 and D2 reduce the usb data lines to USB high of 3.6V. Diode D3 prevents USB 5V transients or overvoltage from damaging the 5V regulator chip V1 or the rest of the components. The device does not appear to be just a USB device. It also has it's own power input for standalone operation. The diode ...

0

I did a little research into the silicone caulking application and contacted the customer support email for a tube of silicone caulking I happened to have on hand. Here's the exchange... Here's my message... --------------- Original Message --------------- Comments: I was told that 100% Silicone caulking, in this case clear caulking, in ...

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