Microsemi seem to go out of their way to design PIA parts to solder 😊

-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Steve Gregory
Sent: Thursday 25 June 2020 18:11
To: [log in to unmask]
Subject: Re: [TN] [External] [TN] Soldering Microsemi VSC8522XJQ-02?

Hi Dave,

Thanks, that's what I thought. I've been through Microsemi's site to try and find some sort of footprint or application notes or something to help, and there isn't anything I can find.

Funny thing about this is, is that this part is coming with a new board that we're quoting and it's supposed to be for a new prototype, but the last time buy for this part is this coming August! Sheesh!

Probably not making it anymore because nobody wants it because it's such a PIA to solder!

Steve

On Thu, Jun 25, 2020 at 10:59 AM David Hillman <[log in to unmask]>
wrote:

> Hi Steve - I took a quick look at the component and if the intent of 
> the package design is to have that center pad soldered to the assembly 
> then run! As you mentioned, trying to get a solder paste/solder 
> wetting balance between the center pad and the outer I/O pads is a 
> nightmare. A QFN would be easier to solder than this package.
>
> Dave Hillman
> Collins Aerospace
>
> On Thu, Jun 25, 2020 at 11:44 AM Steve Gregory <[log in to unmask]> wrote:
>
>> Hi All,
>>
>> I just ran across a new part that I've never seen before from 
>> Microsemi, it's part number VSC8522XJQ-02. Microsemi calls it a TQFP 
>> package, but's not like any TQFP package I've seen. Well, actually 
>> I've seen something almost like it from quite a while ago from LSI 
>> Logic I think it was, they called a "Fusion" package. It had dual 
>> rows of leads like this does, one set on the outer perimeter, and 
>> another set inside around the middle of the body like this one does. 
>> But this one has a thermal pad like a QFN and the two sets of leads 
>> are on different pitches, and different types. The perimeter leads 
>> are gull wing, and the inner pattern pads ar like rounded rectangle 
>> BGA pads.
>>
>> I remember that the fusion part took me three versions of stencils to 
>> get the part to solder right even when the manufacturers 
>> recommendations were first followed. I'm hoping I don't have to go 
>> through that drill again with this part. I'm hoping that someone out 
>> there in "Technet Land" has used this part before and can set this 
>> old fart's mind at ease...
>>
>> TIA,
>>
>> Steve
>>
>> --
>> Steve Gregory
>> Kimco Design and Manufacturing
>> Process Engineer
>> (208) 322-0500 Ext. -3133
>>
>> --
>>
>>
>>
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--
Steve Gregory
Kimco Design and Manufacturing
Process Engineer
(208) 322-0500 Ext. -3133

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