hello,
We need to replace the OSD32MP157C-512M-BAA in our board.
Can you send relevant data for soldering this device? (reflow graphs, etc.)
I have looked into ST AN2639 but it provides information regarding the STM device only, not the Octavo OSD32MP one.
thank you
Gil
hello,
An update:
This will be a selective reflow process (replacing only the device and not a reflow of the entire pcb).
Is the soldering profile different than the one for a full pcb reflow?
thanks,
Gil
Hi Gil_he,
a very difficult thing to do. Don’t use any hot-air stuff. I have broken a few OSD the final result shortcuts 5V to GND inside the chip. The only good way is reballing machine with the profile plus new OSD32 with fabric balls. I suggest something like below
The bottom heater is set to 150C
The upper IR heater profile as follow
It is good on my machine. Sometimes I need to do this process twice, and I don’t know why.
Fabric pieces have balls on pads if You make reballing You need to set balls on PCB. I make a few experiments to give OSD32… on back than stencil + balls and rebaling machine or hotair to solder the balls. This process finished quite good, but when I figurated OSD32… on PCB and even used reballing machine with a good profile always achieved shortcuts on 5Vto GND. It is very strange I have had no issue like this before. This chip is very complicated inside, nano PCB with the IP cores. I feel that some lead during increased temperature leakage on neighbour pads makes shortcuts, of course, inside the chip. I don’t recommend reballing for this OSD32.
gil_he,
We recommend checking the PCB shop you work with on their rework capabilities. You can take a look at https://www.ti.com/lit/an/slva439a/slva439a.pdf.
The soldering profile is does not change for replacing the part. However, note that you will need to bake the replacement part before you put the board through reflow to avoid any MSL related failures.
Best,
Neeraj
mwlinux,
Did you bake the replacement part before putting the board through reflow?
Best,
Neeraj
Thank you Neeraj
Hi mwlinux,
We sent the board for a selective reflow replacement of some other device, and the board came back with the OSD32 defective.
The PMIC_BUCK4 gives a wrong voltage (very low).
I wonder if the replacement process somehow damaged the OSD32.
So, we want to remove the defective OSD32 and place a new OSD32 instead.
I understand the difficulties you mentioned are with regard to assembly of a used device, not a new one. Is that correct?
So, we don’t need any reballing.
Take the stencil we have, take a new OSD32 out of the bag, bake it (or not) and assemble according to the reflow you posted.
Am I correct here?
Do we also risk the 5V to GND shortcuts?
Thank you,
Gil
Hi,
with new pieces and a soldering IR station machine with profile, I have no issue.
Neeraj,
I think that baking is not a problem because after achieving a shortcut in 5V to GND and again reballing (reablling I mean chip on back, balls and hot-air) shortcut disappears. But again soldering causes a shortcut between 5V to GND. After such rebaling procedure 1 at 10 times, osd32 is back to normal work. So I guess that some lead material is sometimes short sometimes doesn’t. But this is only my feeling nothing else, I’m not an expert with soldering.
BR
Michal
I have broken about five pcs in the same way. If it is possible, I can send that pieces for investigation.
BR Michal
Hi Michal,
Do you recommend using the reflow profile you sent for soldering a new OSD32?
thanks
Gil
Hi Gil,
yes, I used the presented profile for this chip, but everything depends on Your soldering machine. I suggest the last phase change to 20 seconds. Nevertheless, remember to bake chips before soldering and adopt the profile to Your board and Your soldering machine. I can’t guarantee success, I made a few tests after achieving a good result.
BR
Michal
hello Neeraj,
Are the solder bumps (solder balls) on the OSD32 Pb Free?
Should we use a Pb Free or SnPb reflow profile?
I understand the Peak temperature is package dependent.
Can you send a recommended reflow profile for the OSD32?
thanks
Gil
Ok it wasn’t my design the problem, same problem for me I have lost 5 OSD (shortcut 5V GND).
And now I’m waiting for another chips from my distributor
I use this oven for prototype
peak 240°c
The chips OSD are very expensive and not available (mouser, digi-key…), not easy for prototyping
Best regards
Alexandre
You can see a ball of solder gets out from component.
What type of solder is used in the chip? Low Temperature?
5V and GND are in shortcut
alexandre,
I am not sure what process the SIP pictured went through. If the SIP experienced delamination and cracking, then solder could come out from inside the SIP(could be MSL issue) but that may not be the cause of problem. Cause could be BGA desoldering process which could overheat the part for quick remove.
If it is MSL issue, please make sure you are following storage and reflow requirements described in sections 9.2 and 9.3 in the datasheet(https://octavosystems.com/docs/osd32mp15x-datasheet/)
Are you replacing or re-using the SIP? If so, you will need to be very careful not to damage the SIP.
You also need to dry bake board before removal and bake part before replacing on the baord. Board drying specs are different (lower T and longer duration).
Best,
Neeraj