Required recommended PCB land pattern design and reflow profile for part# LMZ14203HTZ/NOPB.

Hi Vinoth,

I haven't heard from you in a while.

I'm going to assume this issue is resolved.

Thanks,

Andrew

HI andrew

sorry for late reply.

we are using part # IC-LMZ14203HTZ/NOPB in one of our power module product.

after reflow soldering process, we found that part leads has short.

we set all parameters as per part data sheet suggestions but still issue persist.

PCB thermal pad was tented by solder mask at bottom side of PCB. is it cause to solder short?

could you help on this.

its lead internal short not a solder short.

Hi Vinoth

Which leads are shorted?

Thanks,

Andrew

hi Andrew

its 4 and 5th pins

Also Could you share your Schematic/Layout? I wanted to see what you ended up doing with the Vias.

Finally, is it possible take a photo of the PCB with out the IC and on the bottom?

okay i will share shortly

same failures was reported earlier and texas done some improvements from their end , could you please update status of those.

find the documents details:

Generic 8D REPORT
Power Module LMZ12xxx & LMZ14xxx  

Cold you re-upload the files? I don't see them.

Thanks,

Andrew

Hi Vinoth,

When you removed the parts, are pins 4 and 5 still shorted?

Did both of the IC's (U52 and U53) on that PCB have the issue?

Thanks,

Andrew

It looks like there's quite a few untented/unplugged vias on the top layer.

Could you check if pins 4 and 5 are shorted when the LMZ14203HTZ/NOPBs are unsoldered from the PCB? Also could you please send your layout and schematic?

Thanks,

Andrew

hi Andrew

find my answers in greens

When you removed the parts, are pins 4 and 5 still shorted?

yes, removed parts had short

Did both of the IC's (U52 and U53) on that PCB have the issue?

yes, both IC's has issue

its fully tented on top layer and part were removed from PCB on those pads so its look like partially tented. 

Trails:

1. components are tested prior to reflow soldering process and found that no short on leads

2. after completing reflow soldering process found that leads has shorts (Reflow soldering temperature has been set as per data sheet recommendations)

Hi Vinoth,

Could you share the reflow profile? What temperature are you operating these at?

Thanks,

Andrew

That should be ok. Where did you get the parts from? Could you take a picture of the package they came in and top mark?

Thanks,

Andrew

Hi Vinoth,

I will check and get back to you.

Thanks,
Andrew

Hi Vinoth,

Could you check with Arrow to get the documentation/invoice of the material purchased?

Also, are you having issues with devices from that reel set, and ones with that top marking?

Thanks,

Andrew

Hi Andrew,

we have issue in different invoiced materials.

for further discussion share mail id and i will share invoice details thur mail.  

Hi Vinoth,

I got your mail.

Thanks,

Andrew