Diode direction silk screen missing

[AndreiUlmeyda]

Hey there, me again.

I've got all the parts together now and am in the process of soldering the board. I've noticed that on the older board (which still had the rad icon printed on it ;) there was direction information for diodes visible on the silk screen. It appears to me this is missing on the new board, as I imagine they are still directional components.

For now, I will try to infer the direction from the schematics.

Cheers, mate

[AndreiUlmeyda]

Update: Ive just downloaded the gerber files and opened them in KiCad. It seems the silk screen there contains a line for each of the diodes indicating the direction. So either I've just ordered using older gerber files or the print wasn't the best. The board itself says its Rev2.0

[NuclearPhoenixx]

I've just checked the Gerber files again and you should definitely be able to see the cathode line. Maybe on your silk screen print it got lost to the adjacent pad, because it's really close to it? I don't know to be honest, there should be a line. Where did you order your PCBs?

[AndreiUlmeyda]

I ordered at JLPCP, heres a blurry picture of the situation, apart from that the board actually looks awesome .

[AndreiUlmeyda]

Another issue I've had is the orientation of U7 and U8. The markings of the 6pin versions, at least the one I've got, do not have a dot at all. They look like this, with the single dots being rougly where the pins are Here the datasheet, but I could not figure out if O, A, D and I refer to the pins in some way. I've soldered 2 of them under the assumption that the only asymmetrical feature, the bar over the I, corresponds to the location of the dot. Maybe I am being hasty, though. Do you have an idea about how to determine the orientation?

[NuclearPhoenixx]

I ordered at JLPCP, heres a blurry picture of the situation, apart from that the board actually looks awesome.

Okay, that is actually weird. In the JLCPCB Gerber preview it looks fine, but with Aisler it looks like that:

How much you can see of the small lines might depend then on the manufacturer. There is clearly a problem with the margin around the pads, I'll have a look at updating the diode silk screen to fix it. By the way, nice purple color you got there!

Another issue I've had is the orientation of U7 and U8. The markings of the 6pin versions, at least the one I've got, do not have a dot at all. They look like this, with the single dots being rougly where the pins are

Here the datasheet, but I could not figure out if O, A, D and I refer to the pins in some way. I've soldered 2 of them under the assumption that the only asymmetrical feature, the bar over the I, corresponds to the location of the dot. Maybe I am being hasty, though. Do you have an idea about how to determine the orientation?

Actually the OADI is just the SMD device marking refering to the OPA357AIDBVR, OPA357AIDBVT or OPA357AIDBVTG4 which has nothing to do with the pinout. The wide bar to the left of the SMD code is the actual orientation marking. So it has to be oriented like that (grainy screenshot):

In general with most of these packages pin 1 is always to the left of the SMD code when you orient it so that you can read it. I have no idea what the other (horizontal) five bars mean though.

[NuclearPhoenixx]

Here is a sneak peak of the fully manufactured board (coming soon) that will probably help you. Here you can clearly see how all the components are laid out:

[AndreiUlmeyda]

Aight, that means I took my 50/50 chance with the orientation and bombed it like a champ ^^ Thanks for being so helpful! I will try de- and resoldering them.

nice purple color you got there

ikr :D

Give me a hint should you mind my pestering you with issues like that ;)

Have a very nice day

[NuclearPhoenixx]

Give me a hint should you mind my pestering you with issues like that ;)

Oh no worries, that's what issues are here for ;)

[NuclearPhoenixx]

@AndreiUlmeyda Quick question: did you order multiple boards from JLCPCB? Do they all have the same silk screen issue? I know that silk screen by JLCPCB can be a bit wonky sometimes, so it would be good to know if it's a consistent issue 👍🏻

I just checked with my board made by makerfabs that I have lying around here and you can clearly make out the cathode line. It's close to the pad, though.

By the way, unrelated but make sure to change the 49.9Ω R3 to a 1k -- it decreases noise at lower energies!

[AndreiUlmeyda]

@Phoenix1747 Hey there, it is very consistent over 5 boards, presumably all from the same batch. 3 diodes each, no cathode line even if one knows where to look. A little update on the project: I've noticed that I am missing the SIMP carrier board x]. And I've inspected the alternative SIMPs I've bought. I really hope my soldering tip is small enough to be able to solder the BGA stuff. Luckily, there do not seem to be that many different different and/or close together leads, fat fingering a few balls together at the rough position of each lead could work.

An important question, though. Is the carrier board likely to be applicable to the alternative SIMP or are there modifications one would need to apply. If so, would you be able to provide guidance there?

Cheers

Update: I've bought 2 pcs of the SIMP you recommended in #12

[NuclearPhoenixx]

And I've inspected the alternative SIMPs I've bought. I really hope my soldering tip is small enough to be able to solder the BGA stuff. Luckily, there do not seem to be that many different different and/or close together leads, fat fingering a few balls together at the rough position of each lead could work.

Fortunately, there are only two signal levels on there with many other floating balls so you should be able to get it running.

An important question, though. Is the carrier board likely to be applicable to the alternative SIMP or are there modifications one would need to apply. If so, would you be able to provide guidance there?

I created the carrier board way before I even got to know this new SiPM and they have a completely different footprint so there is no way you can adapt it in its current state. I wanted to create and test a new board for a long time now, so I hope I get to it eventually. There is so much other stuff happening right now though, so feel free to help. Hope I understood your question right :D

[NuclearPhoenixx]

Should be fixed by Rev 3.0. Let me know if you still have this problem with the new diodes!