Sometimes also leave some pads on non-circuit area
of external lay of PCB for plating current uniformity, so that can reduce
PTH copper thickness difference in different holes.
no special chinese name for dummy pad in this case. same meaning as false
pad.
Best reagrds
Jason Liu
Asia Pacific Strategic Sourcing
SDE
TRW Systems Consulting Services(Shanghai) Co., Ltd.
5F, 62 Building, 421 Hongcao Road,
Shanghai 200233, P.R.China
Tel:+86 21 6120 1166 or 6120 2266
Dir Tel:+86 21 6121 1811
Fax:+86 21 6120 7058
Mobile:+86 138 1895 6432
Email:[log in to unmask]
In the plated through hole of a multi-layer PCB the terms that are typically
used for pads are “functional” (pads that actually carry a signal to
the PTH) and “non-functional” (pads that DO NOT carry a signal to the
PTH). This may be what is meant by “active” and “dummy”.
The designer has 2 choices for pads when designing a PCB.
First is to include pads on each layer connecting to the PTH. This
would include both functional and non-functional. This has the benefit
of reducing the amount of resin in the z-axis and therby reduces overall
z-axis expansion of the PTH when exposed to heat. The negative side
to this approach is that it leaves many more opportunities for “shorts”
between the non-functional pads and the surrounding circuitry.
The second choice is to remove these non-functional (non signal carrying)
pads from the design. This significantly decreases the possible failure
due to shorts, but increases the resin content of the PTH area and increases
the Z-Axis expansion during heat exposure.
From: TGAsia [mailto:[log in to unmask]] On Behalf Of Chris Katzko
Sent: Tuesday, May 15, 2007 4:42 PM
To: [log in to unmask]
Subject: [TGA] 答复: Re: [TGA] active pad and dummy pad
Good question,. Is it Active/Dummy pad for PCB or for BGA component?
In the case of BGA, the Active pad would have electrical connections, the
Dummy pad would be for mechanical attachment and thermal enhancement.
C.B. Katzko, CTO
Meadville Group
e-mail [log in to unmask]
tel +86 21 5774 6907
fax +86 21 5774 0635
mobile +86 13817362590
Who knows those two items "Active pad" and "Dummy pad"
in Chinese?
Many thanks,
Regards,
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