I was just doing some research about the character of the boards we assemble here at Screaming Circuits and some of the data is pretty interesting. I looked at work we've done from 2005 until now and split out the types of components that we put on the boards.
We don't ask a lot of questions, so there is some information that we can't get. Like, for example, we count all discrete SMT parts that aren't fine pitch or leadless as the same thing. So, an SOIC-24 is lumped in with an 0201 resistor. It would be interesting to track the size of passive components over time, but we just don't ask that question.
The character of the orders is pretty similar. The average job in 2005 had just about the same number of individual PCBs to put parts on to as did the average job so far in 2008. They both had virtually the same number of line items on their Bill of Materials.
The number of thru-hole components per board has dropped by 13% over that time. That's understandable. Thru-hole are getting more expensive and things like reliable connectors are starting to become more common in SMT form factors.
Fine pitch parts - leaded parts with 20 mil or less lead spacing, like QFPs and those thin flat-pack flash chips - have gone down more that any other type of part - by 20%. At first that really surprised me, but after thinking for a bit, I began to suspect that these are moving to BGAs and QFNs. The flat pack flash chips do seem to be going to BGAs and microcontrollers that used to show up as thru-hole or fine pitch QFPs seem to be coming more commonly as QFNs.
Leadless parts, like BGAs and QFNs are up by nearly a factor of three! This is very much to be expected. More and more parts are moving to these smaller footprints. I wish we could split out BGAs, microBGAs (.5mm or less ball pitch), QFNs and CSPs.
Last year, the QFN seemed to be all the rage. ZigBee radios are all QFNs. Micro controllers seem to be going to QFNs and even dual row QFNs. We're seeing a lot more .5mm pitch BGAs too. The ARM32 processors all seem to by .5mm BGAs. Bluetooth modules are mostly small BGAs also.
The surprise to me is the power components. Things that used to be in big hulking TO-220, TO-263 and similar packages are now showing up as QFNs and Chip scale micro BGAs. I ran across a little 1 Amp motor driver in an 8 lead QFN package a while back. Amazing. A lot of the new Buck and/or boost chips are showing up in chip scale micro BGAs too. Same for serial flash chips.
We're aware it's a small world after all. Are you?