[PCB_FORUM] Re: Multi-layer stackup design
- From: "Jose Magnaye" <josemagnaye4@xxxxxxxxx>
- To: icu-pcb-forum@xxxxxxxxxxxxx
- Date: Wed, 22 Feb 2006 12:56:15 +0800
Yes, our standards specify at least 0.41mm if using a core material
(laminate). If less than or equal to 0.40mm then we need to specify 3 layer
prepreg (sorry for the wrong spelling before) but there were no minimum
thickness specified.
After asking several vendors we also found out that there are no published
dielectric breakdown voltages for prepreg materials so we cannot compute for
the minimum. Of course we can always use the 2.0mm PCB thickness but
without proper justification (i.e. literature or computed values), how can
we convince our sales dept and the customer to go with the higher PCB price?
BTW, is this Off-Topic? Are we allowed to discuss things like these here?
- JM
On 2/22/06, richard moffat <richard.moffat@xxxxxxxxxxxxxxxxxxx> wrote:
>
> 0.2mm? Possibly (dare I say probably without any legal ramifications?)
>
> The kind of spec it looks like you're referring to calls for 0.4mm.
> However, that figure is negotiable. Creepage distance on the outer layers
> is more troublesome.
>
> You're certainly doing the right thing by layering more than one prepreg.
>
>
>
>
> __________________________
> Richard Moffat
> PCB CAD Manager
> Allied Telesis Labs
> ph. +64 (3) 3393000
> richard.moffat@xxxxxxxxxxxxxxxxxxx
>
> >>> josemagnaye4@xxxxxxxxx 22/02/2006 3:51:48 p.m. >>>
>
> Hi Claude
>
> We're trying to design it to be as generic as possible since we will be
> using several vendors. They can define which materials they can use for the
> prepeg but the stackup design should be fixed.
>
> Basically what we are trying to determine if 0.2mm thickness will be
> enough for the 3 layer prepeg to withstand at least 1.5KV.
>
>
> On 2/22/06, Claude Meyers <claude.meyers@xxxxxxxxxxxxxx> wrote:
> >
> > This is a question you should be asking your fabrication house. Every
> > PCB Fab house has different requirements.
> >
> >
> > ------------------------------
> >
> > *From:* icu-pcb-forum-bounce@xxxxxxxxxxxxx [mailto:
> > icu-pcb-forum-bounce@xxxxxxxxxxxxx] *On Behalf Of *Jose Magnaye
> > *Sent:* Tuesday, February 21, 2006 6:00 PM
> > *To:* icu-pcb-forum@xxxxxxxxxxxxx
> > *Subject:* [PCB_FORUM] Multi-layer stackup design
> >
> >
> >
> > Hi!
> >
> >
> >
> > We are designing an AC-DC power supply on a 4 layer board and we are
> > currently looking at any literature on how to design the stack-up.
> >
> >
> >
> > Some of our primary and secondary tracks overlap and we were told that
> > we can let them overlap as long as we use 3 prepeg layers in between.
> > Unfortunately, we cannot find any info on the minimum allowed thickness of
> > the 3 layers.
> >
> >
> >
> > We are concerned with the thickness since we will be using a 1.6mm 4
> > layer FR4 board with 2 Oz copper on all layers.
> >
> >
> >
> > JM
> >
> >
> >
> >
> >
>
>
>
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