[PCB_FORUM] Re: AMC format

Hot Swap?

 

________________________________

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Macindoe, Gary
Sent: Monday, October 30, 2006 3:09 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: AMC format

 

Thanks for the reply Jeff.  I think I'd better keep the sections closest
to the card edge since it does show it in the spec.  Yeah, that was my
first thought, it looks like you don't even need those.  But then, why
does the spec. show them?

I think I'll play it safe and put them in, probably as mechanical pins.

 

Regards,

 

Gary E. MacIndoe

PCB Design Engineer

Advanced Micro Devices

Longmont, Colorado

________________________________

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Jeff Schmitt
Sent: Monday, October 30, 2006 10:35 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: AMC format

 

Gary,

 

I've done a few custom connectors like this.  IMO, there is no need for
the section closest to the card edge so I would design it out.  I put a
pin escape via just above each connector pin and routed a trace back off
the card edge (one for each signal) on an internal layer in the center
of the stackup for a plating bar.  I let the fabricator bring the
plating bar out to the external layer of their choice.  Putting the
plating bar in the center of the stack-up prevents the traces from being
exposed after the chamfer is added.  This will cause a fairly long stub
on each signal pin so make sure you check with engineering prior to
using this method.

 

Make sure you put a no route area on that layer under the connector pins
prior to routing.

 

Jeff

 

________________________________

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Peter Hughes
Sent: Monday, October 30, 2006 11:06 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: AMC format

 

Hello Gary,

 

We have done a few of these boards and the way we do the edge connector
is to build each finger as two pads. Referencing your diagram below the
pads that are on the left of each finger are a mechanical pad with no
connection but the pads on the right are a connected pad with the pin
number.

 

As for the gold fingers a selective plating process was used.

 

Rgrds

 

Peter Hughes,

PCB Designer,

Concurrent Technologies,

4 Gilberd Close,

Newcomen Way,

Colchester,

Essex,

CO4 4WN.

Tel: +44 1206 752626

Fax: +44 1206 751116

-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Macindoe, Gary
Sent: 30 October 2006 16:41
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] AMC format

 

Hey guys,

 

I'm doing an Advanced Mezzanine Card (AMC) format design and have a few
questions.

 

This format has an edge connector on one end with a strange contact
pattern.

As opposed to the normal (i.e. PCI) edge connector fingers (all the
same), this format has some two part fingers that connect sooner or
later than others (see diagram below).

 

My first question is about creating the pads/symbol for this edge
connector: as far as the two part padstack fingers (Second, Third & Last
Mates), how would you create them?

 

My second question is concerning gold plating this strange finger
pattern.  It seems to me that the only way is "selective plating", as
opposed to the normal edge connector plating process, correct?

 

We're in a state of flux right now, not sure which fab house to ask, so
I thought I'd ping you guys.

Thanks for any responses!

 

 

 

 

Gary E. MacIndoe

PCB Design Engineer

Advanced Micro Devices

Longmont, Colorado

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