Re-Package.COM

SO-8/14/16 Carrier PCBs

(2008/10/14)

 

Here's the first set of carrier board designs for SMD SO-8, 14, 16 and SOJ-16.

 

Why are we making these?

Well, because we actually need them ourselves. The last few months were hell with numerous little development projects with

little funny 8 pin and 16 pin SMD chips. In a hurry I would solder them with fine wires under the microscope or design

a PCB, wait 3 to 5 days for the proto and then continue development. Have you ever calculated how much time you lose

when you have to pick up a project again after a week? Also the personal drive goes down and many times the project

take 200% as long to finish. Also, you rush the PCB and when you get it back you realize you made a mistake on the board,

maybe requiring a difficult modification or, even worse, a total write-off. How about this. You are already late (who isn't?) and

now your boss/client is breathing down your neck. And your excuse? The PCB is on its way. And then you get it and you realize

the concept doesn't work at all. Man, then you are screwed!! Wouldn't you like to rather experience that disappointment

two weeks earlier, when you still had a job?

The development scene has changed in the last few years. In the early 90's I would attend a meeting and my boss would tell me

what I should have complete by Friday (this week). Now engineering meetings are long boring planning meetings discussing

when what would arrive, who should it be outsourced to and how many weeks from now will be have it in hand....and everybody

is losing money and time...and their lives are ticking away...

These carrier boards are just one of a few simple tools we are planning to speed life up. This particular tool takes your difficult to handle

SMD and makes it accessible on either breadboard, Veroboard or your own custom PCB (which can be cheap single sided, made-with-

Positive-20-at-home-in-your-bedroom type). So here are some specs.

Spacing:

The spacing conforms to a 100mil/2.54mm grid and the module will fit on a standard breadboard or Veroboard.

Options:

The PCB holes are 36mils, big enough for the square IDC type of connector. The carrier boards will go on sale with the following standard options:

1: Carrier PCB only........................................................................................................

2. Turned pin connectors (for breadboard, Veroboard or custom PCB). More expensive

3. Square IDC pins (for Veroboard or custom PCB). Less expensive.............................

More advanced options:

The standard carriers will be single sided PCBs (with the copper on the top), with a thickness of 1.55mm and 35um copper.

We can manufacture them in double sided as well as with a ground plane (double sided, through hole plated). Here we place a solid bottom copper layer

and place it about 1mm away from the pins. The edge, near the pins, are exposed (no green soldermask) and can be linked to your ground pin(s).

We can have the boards made in other single or double sided sizes (0.8mm, 1.0mm or 1.2mm - only single sided) or double sided only (2.0mm,

2.4mm or 3.2mm).

Also, if you require more current we can either customize the particular tracks you require to be thicker or we can order the PCBs with 70um

thick copper.

For all these extra options we will charge and average of R1000 (one time only) as there are engineering and tooling costs to cover. The boards

will also cost more than the standard boards (sometimes more than double even at high volumes). When you want to "go custom" then don't

think small and just buy one board. A single board will cost you hundreds of Rands. I will take your money, but I won't think that you are very smart.

For higher volumes I will provide you with a sliding scale so you can make an educated choice.

If you require thousands of carrier boards (3000 to 4000+) then the local South African board costs too much per unit. We will then buy from

a Chinese manufacturer that will cut 30% off our local price.

Please note that any custom order will take a minimum of 3 weeks and up to 12 weeks (if we don't have connectors ex-stock).

 

 

Other features:

You will be able to buy the PCBs per sheet (number depends on layout and size). You will notice a round (red) pad at around pin 1. This is a 1mm

pad called a fiducial or reference mark. This is used by pick and place machines to position the head during placement. So you can mass populate

your own boards with your own components if you want. If you want to do that we will send you the paste Gerber file so you can make your own

solder stencil. Note that the sheets have guide edge of about 8mm on two edges which adds area, and thus also cost.

 

You will also notice a piece of copper under the component (the red section in the middle of the PCB). Many newer components come out

with a thing called a "power pad". This is used to either bring out ground and or heatsink area. There is a extra pad where you can make a

connection to. To bond such a chip is fairly easy. You make a little blob of solder on the big pad, apply flux and gently heat with a heatgun. To simplify things

you can preheat the PCB to about 150 degree celcius, on a stove (preferably on a flat surface), and then add the added heat from the heat gun. Then

hand solder the rest on the pins. If you have SMD rework equipment, or access to it, I would suggest using it.

Decoupling: Please note:

No provision is made for decoupling capacitors. These are ideally placed as close to the power pins as possible. Because there

are so many different pin configurations we have decided not to attempt to make any other connections. The user will have to solder,

if required, a through hole type capacitor over the two power pins.

Orders, packaging and shipping:

Note that the connectors will be supplied unsoldered as the connector pins will be in the way, and especially if you want to reflow the power pad.

So you will receive 2 connectors for each carrier PCB (if ordered with connectors). This also alleviates our stock problems of keeping 3 different

versions on the shelf.

The PCBs are fairly cheap (final costing to be done after the prototypes have come back to us). BUT the shipping is expensive. Here in

South Africa you can pay anything from R45 (slow and high risk) to R100 (fast, insured and overnight). International orders are even more scary and

can take up to 8 days (if your custom office is faster than ours). So we will probably impose a minimum order quantity to level out the cost. But if

you really want to buy just one then we sell it to you, but you will still need to pay the shipping (that will be many times more than the cost of the

carrier PCB).

Also,  this component's cost is very much linked to quantity, so the more you buy the lower the price will be.

Packaging will also be an issue. You will be able to buy them in a stack or per sheet. Per stack will be the cheapest. We ship per volumetric mass. This

means that you pay either per mass (+ initial handling fee-box, wrap, bags + labour) or LxBxH (cm) /5000 x  the rate + handling fee. The shipping company

charges the option which is the greater of the two. So in theory the stacked PCBs will be cheaper to ship as the sheets need to be strengthened (more volume) and

extra insurance must be bought because a snapped sheet constitutes a broken shipment (because you cannot place that in a P&P machine).

For the people that live in the Pretoria/Johannesburg area I will try to deliver some stock to places like Communica,  Electrocomp and maybe Yebo Electronics (but keep

in mind that they will put on a hefty profit for themselves).

 

Warranty:

We will visually inspect each unit before packaging under a stereo microscope. When we start to do large volumes the boards will be automatically tested at the

PCB manufacturer. So the warranty only covers cracked tracks, open circuits and shorts. As soon as you start soldering on the board the assumption

is made that you have inspected it yourself and the warranty is null and void.

Also note that the thinnest tracks are 12mils wide and are not designed for high current. Burnt off tracks and lifted pads are not considered manufacturing faults

but rather seen as abuse.

Storage:

The connections are hot air leveled tin. When we get the boards we try and only handle them on the edges or with white gloves. Any moisture

or oil (even dust, too much oxygen) etc... causes the deterioration. By the time you receive it the tin layer should still be considered new, but after a

while these environmental conditions will reduce the solderability of the junction. So keep the stuff in the bag until you are ready to use it. If you

have to play with it then play with just one (for your show and tell). Also, don't play with a static sensitive device after soldering it to the

carrier board as you have just brought out more length to the pins to receive a damaging voltage spike.

 

Payment options.

For now we will accept cash (who wouldn't?), EFT bank transfers and credit cards (via http://www.setcom.com).

For cash and EFT we will discount you the 4.9% transaction fee charged on credit cards (but this apply only to South African

clients for now).

We are VAT registered and will be able to provide you with an official VAT invoice.