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Posts: 79 | Thanked: 719 times | Joined on May 2014 @ Buenos Aires, Argentina
First of all, there's now also a "standalone" version of the roadmap:

I tried to go light on the jargon in my previous post, but some of it may still be puzzling. Here is what it means, with a bit of background:

PCB (printed circuit board) refers to either a bare board (without components), or a board with components (but not assembled into a case or such). When the meaning could be ambiguous, "PCB" is used for the bare board and PCBA for the board populated with components.

PCBA (PCB Assembly) is a PCB on which all the components have been soldered (SMT). A PCBA is the product of a) making the PCB, then - in the case of SMT - b) placing the components, and c) soldering them. A PCBA can typically perform a large number of functions and can be conveniently tested in isolation, before putting it into a case or similar.

In the case of the Neo900 project, we'll call the PCBA "NeoN" and the assembled device (i.e., Neo900 PCBA plus case and circuit parts from a Nokia N900) "Neo900".

SMT (Surface Mounted Technology) refers normally to the technology as such or to anything that is related it, but in jargon it also refers to the soldering process used for such components. An SMT factory typically has one or more production lines in which bare PCBs are first covered with solder paste, then the components are placed on the boards, and finally the result passes through an oven where the solder melts and forms the contacts. If a board has components on both sides, the process is repeated for the other side.

BOM (Bill Of Materials) is a list that includes all the parts that go into a product. A typical BOM would include entries that contain things like "24 Resistor 0402 10kOhm 5% 1/16W", possibly a list of locations where this resistor is used in the circuit in question, and often also a part number. The part number can be a manufacturer part number, e.g., "Samsung RC1005J103CS" or an orderable part number of a distributor, e.g., "Digi-Key 1276-4400-2-ND ".

Priced BOM is a BOM that also includes current pricing information. E.g., for the resistor above, it may say "USD 0.00125" per unit, "at 30000" units. Note that not all pricing can be found by just looking in a catalog, so adding this bit of information can involve some haggling.

I didn't use "BOM" or "priced BOM" in the article above, but "BOM cost". The BOM cost is what it costs to purchase all the materials that go into a PCBA (or possibly the whole device.) The BOM cost is only a small part of the total cost of manufacturing a device, especially at quantities that aren't in the millions of units.

- Werner

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