Originally posted by n9352527@May 21 2006, 10:59 AM
The 18F4550 USB PIC (40DIP) is available in the UK from Farnell (for around £5), I have no idea about the 28SDIP USB one (18F2455?). They are compatible though, only different IO number and flash memory size.

PIC programmer is quite cheap to obtain, or make yourself. And once you've got a programmer or access to one you could burn a small bootloader program so that further programming could be performed through USB link without any programmer (enhanced flash self programming).

I have a conical tip for soldering iron that is excellent for smd soldering. It uses the surface tension insode the cone to dispense just the right amount of molten solder and prevent bridging and too much solder. I'm pretty much able to solder most of the smd components/packages manually except for things like BGA packages where the pins are not accessible. It is not that expensive to buy, but you would also need additional flux to work with it (and probably flux cleaner too).

[post=17260]Quoted post[/post]​

Be careful about overheating SMDs -- get it onto the board fast! There is such a thing as a SURFboard, a small daughter board designed to hold one or two ICs and just a few surface mount Rs, Ls and Cs. Maybe RadioShack?

 

Originally posted by n9352527@Jun 7 2006, 06:04 PM
I'm fairly sure it was a SOT23 and not that bigger SOT223 with flat tab. I used to work with them both in another life at a semiconductor manufacturer. The gap is not that bad, bigger than SOIC or quad flat which can still be carefully soldered manually.

[post=17601]Quoted post[/post]​

I have attached (a very poor) photo of SOT23 along side a USB head - I couldn't think of anything else that would show the size of SOT23 that most people would recognise.

I apologies for the poor quality and the fact that I had to paste the image into a Word Document, but it should at least jog you memory.

Dave

 

Originally posted by Dave@Jun 8 2006, 08:14 PM
I have attached (a very poor) photo of SOT23 along side a USB head - I couldn't think of anything else that would show the size of SOT23 that most people would recognise.

I apologies for the poor quality and the fact that I had to paste the image into a Word Document, but it should at least jog you memory.

Dave

[post=17631]Quoted post[/post]​

I think the crowd will get the idea from the photo. They maybe small but not that hard to solder.

billbehen said:

Be careful about overheating SMDs -- get it onto the board fast!

SMD components are no more suseptable than leaded components to heat. If you hold your iron on a pin for more than 3 seconds to form a good joint you have a problem. If the pad and pin have been cleaned and fluxed correctly prior to soldering then it should take less than 2 seconds to complete the joint.

Just a bit of background. I taught soldering to DoD2000 standards which was the US Department of Defence document that details the soldering procedures used by the US military and also NASA.

If anyone would like some hints on soldering just yell.