Tim,

RE: Stacking 0603 resistors and capacitors (either 3 or 5 sided)

J-STD-001-C points out that this is acceptable (6.4.2.1).
Also as a reference - go to the IPC-HDBK-001 handbook for additional
information on stacking (6.4.3.1). It says it 'should' not be done, but
that means it can be done.

Basically they say - Stack them side by side (billboard style) not
directly on top of each other. Verify no possible height, high
frequency, or electrical clearance violation.  Additionally the
requirement must be properly documented by Engineering on the drawings,
ECO, etc.

Also, when stacked by billboarding - have the numbers facing outward for
value verification and allowing the resistive element the advantage of
air for any cooling requirement.

We have done this usually during prototyping.  We have also seen this
(as a cost consideration) in production of a released assembly instead
of having a board re-spun.

Tom Parkinson
Quality System Manager
WinTronics, Inc.

Tim Devaul wrote:
>
> Good morning,
>
>      I am in the middle of a slight disagreement between a couple of our company's organizations. It is over stacking
> SMD chips, specifically 0603s. In a temporary rework fix engineering wants to stack and solder one chip directly on top of the other. Does anyone have any experience positive or negative concerning this practice?
>
> Tim DeVaul
> Quality Assurance Training and Audit Supervisor
> Philips Broadband Networks, Inc.
> 100 Fairgrounds Dr.
> Manlius, New York 13104
> Tel: (315) 682-9105 Ext. 2403
> Fax: (315)682-9006
> Email: [log in to unmask]
>
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