So, after talking to my electronics professor at university yesterday, he also told me that the circuit should work, using either the AD8001 or the AD8055/56. But he wasn't really enthusiastic about my design, pointing out, that a ground plane is a nice thing to use, but on video circuits you should go double sided, even though the design is that simple, and give it a bit of separation of supply and signal tracks.
Looking at pcbshopper I noticed that there is no real difference in price concerning singlesided to doublesided PCBs, so I will redesign the whole thing and go doublesided. I went with singlesided at first because I thought about making a prototype board myself (aaah, like in the old days...
) but since I neither have etchant nor developer at hand, I would have to buy that stuff.. and since a 5x5 cm board doesn't cost a fortune I will go with doublesided, made in china.
I also looked again at the datasheet and rethought about the decoupling caps at the opamps.
Since I want to produce a high quality signal I went with the schematic they used for testing conditions, because I guess that should be the best possible way to do it. So I replaced the 1nF ceramic caps I used at first with three caps (10µ, 100n, 1n) and placed them as close as possible at the pins.
That was, of course, a little bit more space consuming. So I thought, why not switching to SMD, at least for the passive components. The OpAmps will be socketed. That allowed me to shink that thing further down.
So my goals were:
- redesigning decoupling of V+ and V-
- using SMD
- shrinking to get under 5x5 cm
- moving to doublesided
- trying to use mostly one direction per layer (top -> horizontal, bottom -> vertical) to minimize coupling between tracks
By the way, even if my question from the beginning is cleared by now, I would love to hear your oppinions about the project!
As I said, I never did anything concerning video equipment, so any advice is appreciated!
I attached the newest revision of the board and would love to hear what you think about it. I disabled most of the labels so that you can see more of the tracks. thanks!
By the way, since I read a comment on another thread like "why doesn't those small boards have mounting holes!? how do you expect the user to mount it anywhere?" -> I thought about that, the triple RCA connectors I would like to use have holes for screwing to a faceplate.