Well - it just seems like electronic component manufacturers are making components of smaller and finer pitches, and leaving out larger pitch devices (up to and including DIP packages); what I am really after -is- speculation (whether it comes true or not, I don't care) - what do you (or anyone else) think hobbyist electronics might look like 10-20-50 years out? Will it even exist? Will anyone care?
Well, it is all about cost. In a finished product, each component costs the sum of :
- manufacturing the component (chip die, package, etc)
=> SMT ICs are somewhat cheaper to manufacture (the chip is the main cost factor) but SMT passives are much, much cheaper than through-holes, especially our friend the ceramic capacitor, which costs near zero.
- ordering, inventory management, etc
=> again, SMT reels are smaller, easier to use for robots, easier to manage large inventories, this means cheaper.
- PCB space used
=> Obviously smaller means cheaper, but only up to a point, if you need to use premium high-tech PCB fab job for very fine tracks, it gets more expensive.
- placing & soldering costs
=> SMT wins big time, no machine to fold component leads, pick & place robots which look like machine guns, etc
(But for our friend the ceramic chip capacitor, the price of the component itself is probably lower than the rest of the other costs)
HOWEVER
Packages which are very DIY-unfriendly like BGA, chip scale, etc, are expensive (and always will be) :
- to manufacture
- and especially to use (need high tech PCBs, multilayer, very fine pitch, microvias, special robotic placing, x-ray, etc)
So, those get used only when there is no other choice ; when you got 800 ultra high speed signals in a PC motherboard, or you want to fit all the stuff inside a smartphone, there is no other choice.
But for the rest of the electronic market, the manufacturers will not pay more for no obvious return on investment, the cheapest part to buy and use will do the job just fine.
This means there will always be a market for low-cost, easy to use, small but not too small packages, which allow use of cheap PCBs.
Fortunately, those are mostly hand-solderable if you dont drink too much coffee
and with good tweezers.
I use mostly 0805 passives, those are easy to hand solder. 0603 tombstones too much, so is much slower to use. For ICs, 1.27mm SO is really easy, for 0.5mm pitch a flux pen and good technique is needed, but it's not difficult...
I guess this state of things is likely to last for a good while, simply because it is a kind of cost minimum "sweet spot".
Even FPGAs are available in "easy" packages (like 100-pin QFP)... only the low-end models though, but with Moore's law, the new low-end Spartan-6 in QFP are in fact powerhouses !... (the big ones in 1000 pin BGA are just ridiculous)
30 year predictions ? I don't know XD
Some day we will probably 3D-print electronics. Then someone like Ponoko will make a DIY version...
Also 10 years ago if you wanted a double sided PCB made, you'd pay through the nose, now I get a 160x100mm board (double sided plated through) made for 45€ (in Bulgaria)... in a few years you'll get the same price for 4 layers !
Its almost at that point now, except the cheap and easy to use EDA simulation and design software doesn't exist...
Well, that depends. I've made a board with 5 switching converters, PWM with synchronized current sense, microcontroller, etc, and it worked the first time with no modifications. A FPGA board also worked first time (QFP208 was a ***** to solder), but I just stole bits of schematics from reference designs, so no glory
Breadboarding switching converters isn't possible anyway... but you can breadboard SMD parts, using special boards, or simply just a ground plane and putting the ICs dead-bug style (legs up) with a drop of superglue, and through-hole passives. Due to the ground plane, you'll get much better performance than the old perfboard. Old wrapping wire finds a new use !
Also, since programmable parts get more and more common, breadboarding goes inside those... just connect your stuff to the right pins and hack some software. Need a 555 ? Stick a PIC instead
For switching converters, LTSpice is totally excellent (and free). It really works. If you don't like LT chips, TI and others have (free) simulators too.
My first switching converter was a rather complex buck-boost with LTC3780, LTSpice was spot-on, this software really rocks.
For the rest, every datasheet needs to be examined with great attention...
you might want to compare the board design with the original TI design.
Yep, the TI design looks good, more copper and shorter loops.
For switching converters you need to draw (or imagine) the 2 loops the current will go through when switch is open or closed :
1) GND - Cin - top switch - L - Cout - GND
2) GND - bottom switch - L - Cout - GND
And try to minimize loop area of both, inductance before the switches, and capacitance to GND of the SW node. That's about it
> The feedback IS correct.
In fact I was suggesting to take it after the cap (instead of before) to reduce the noise, and increase output voltage precision. But the traces are so short that it may not matter at all.
> TI doesn't use ferrite beads either.
> I guess their engineers know what they are doing.
Their layout sample is a part of a bigger board, so if Vin and Vout are planes, there's no problem.
Your PCB looks like a little module that will be connected using wires (ie, antennas), in this case some ferrites can save lots of headaches. Nothing fancy, a $0.04 murata BLMP or similar...
Also if you use wires, the small Vin pad can easily be ripped off the PCB. Copper islands are more robust.
These switching converters are marvelous, previously it was like dark magic, now :
Digi-Key - AP5724WG-7DICT-ND (Manufacturer - AP5724WG-7)
copypaste datasheet... it works
