Si570 synthetizer module
This is not a full design description, just one possible PCB design and some notes!
As soon as I got one piece of Si570 integrated circuit as a gift from Petr OK1IN I start to think how to build the synthetizer module. The choice of control circuitry was easy - DG8SAQ prepared a perfect design and made it available on internet(TNX!). The connection using USB is very smart, software support is widely available...
The other things is PCB design. My intention was not to build a kit, so I first think to make an own copy of existing PCB. But I realized my expectations are little bit different from that I found on internet, so I decided to prepare own design. The most important point was how to put the Si570 on the board. The goal was to make soldering easy, enable good cooling of IC (for better stability) and alow potential dismouting of IC later (in case I will need it in another design later). Here you can see my solution:
There is a 5x7mm hole in PCB in place where the IC is installed. The oposide PCB side is copper plane; I have seldered there a small metal plate (10x12mm). So there is a small bath where the Si570 can swim (I put a small amount of silicon vaseline on bottom). The pins of Si570 can be connected using just a drop of tin or better (like me) to solder there a small piece of wire - there result can be seen on the next picture.
Here you can see the contruction from top side:
Here you can see the PCB design in ExpressPCB software:
Just for fun - here's the interface to LPT port I used to program ATTiny microcontroller using Ponyprog software:
Some of original links are not alive anymore, so I better attach a circuit diagram...
ExpressPCB design file
DG8SAQ page - hardware & software