Questions about arduino mega assembly

Hello,

I'm trying to manufacture and assemble arduino boards (specifically, the Arduino MEGA) locally (in Brazil) to reduce the cost of the board for some projects. I've analyzed the schematics, and I'm already producing the PCBs. However, I have some questions about the components:

  • Is the F1 component a 500mA fuse?
  • What is the "CE" component. I get it's not actually a component (it's a silk mask), but what exactly is it?
  • Why are components T1 and T2 placed one above the other on the board? Is it so any one of the two ICs can be used? The same happens for components IC4 and IC5.
  • What is the FIDUCIALMOUNT component? On the produced board it's a circular engraving, but what is the purpose of it?
  • What are the specs for the D1 diode? I mean, voltage, current or part number...?

Thanks.

  • Is the F1 component a 500mA fuse?

It is a thermo fuse, the kind that automatically reset when the over current condition is removed.

  • What is the "CE" component. I get it's not actually a component (it's a silk mask), but what exactly is it?

I belive it's a safety rating
http://en.wikipedia.org/wiki/Canadian_Electrical_Code-

Why are components T1 and T2 placed one above the other on the board? Is it so any one of the two ICs can be used? The same happens for components IC4 and IC5.

They are to show that there are optional component part numbers, either one or the other can be used, but only one mounted of each.

  • What is the FIDUCIALMOUNT component? On the produced board it's a circular engraving, but what is the purpose of it?

Don't know without looking at the schematic or board which I don't own.

  • What are the specs for the D1 diode? I mean, voltage, current or part number...?

If that is the polarity protection diode wired between the external power jack and Vin pin & voltage regulator input, then any silicon 1 amp / 50vdc or greater can be used.

Lefty

CE mark:

European Certification mark...

What is the FIDUCIALMOUNT component? On the produced board it's a circular engraving, but what is the purpose of it?

Well there is a similar thing on the duemilanove boards (well the design before the latest modification at least) and I woud also be interested to know why it's there. Maybe for checking the quality of the board or something, a test pad?

Mowcius

Since Arduino started in Italy I would expect that CE means Conformité Européenne ((European health & safety product label)). But of course it could be something totally different Conformité Européenne - How is Conformité Européenne abbreviated?.

Udo

The "Fiducial" components are designed to assist Automatic SMT part placement machinery. Essentially a know shape at a known location so a camera can detect exactly where the board is...

From wikipedia:

"In printed circuit board (PCB) design, fiducial marks, also known as circuit pattern recognition marks, allow automated assembly equipment to accurately locate and place parts on boards. These devices locate the circuit pattern by providing common measurable points. They are usually made by leaving a circular area of the board bare from solder-stop coating (similar to clearcoat), in which a filled copper circle is placed. This center metallic disc can be solder-coated, gold-plated or otherwise treated."

"In printed circuit board (PCB) design, fiducial marks, also known as circuit pattern recognition marks, allow automated assembly equipment to accurately locate and place parts on boards. These devices locate the circuit pattern by providing common measurable points. They are usually made by leaving a circular area of the board bare from solder-stop coating (similar to clearcoat), in which a filled copper circle is placed. This center metallic disc can be solder-coated, gold-plated or otherwise treated."

Ahh, thanks for that :slight_smile:
I wouldn't have known what to look for...

Mowcius

Hello Everyone,

Thanks for all the info! It's been very helpful.

Cya.