Some time ago we reported on Itead’s OpenPCB Service. They offer basic PCB prototyping of 10pcs 5x5cm PCB for $9.90 and 10pcs of 10x10cm for $24.90. For 10 cents extra you can participate in a PCB exchange. 2 extra boards of your design are produced and put into a pool, and you get 2 different open source PCBs in return. We decided to take our chance and see what kind of PCBs we receive.
We sent two 5×5 designs, so we received 4 extra boards from the exchange. In this series we cover which boards we received, and we hunt down the makers and get the story behind the board.
The first board is from a Turkish company called AHSA elektronik. It looks like a switching power supply with some breakouts for difficult to solder ICs. We tried to find some info about this board on their website but we didn’t found any. We send them an email about this board and this their reply:
.. There are two boards with the same marking, I think the marking is an order number or such. The board with breakout boards is a wide input range (9-32V), high efficiency 5V converter. The other one with MOSFET footprints is a 35V converter with same input range and high efficiency. They both have an input filtering and protection circuit. However, these are just some prototypes..
.. Here is the schematic in the attachment. There is one thing to inform, we forgot to merge the ground planes on the bottom layer before sending it to production. That should be done otherwise anode of the schottky diode will inject voltage spikes to the ground plane due to the inductance of the long traces and switching current and will cause a ground bounce which will affect the control circuitry inside the LT3686 chip and this will be the reason for the circuit failure after about 300 mA of load current. The solution is easy, just merge the ground planes with a piece of wire and lots of solder after removing the solder mask with a suitable tool ..
They even cleaned the schematic up for us, how nice! We should do this to all our schematics!
The second one we received is a board from Andrew Salvo with the text ‘Thermocouple Amplifier 2011’ on it. We tried to google him or his board but we didn’t find any usable results. Do you know Andrew Salvo or more about this board? Maybe you are THE Andrew Salve. Please give us a shout via the contact form.
Our bonus PCBs will be added to the free PCB store and can be yours!
Later this week in part 2 we hunt down the designers of the other two bonus PCBs.