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While creating a (my first) device package for this Micro SD socket in CadSoft EAGLE I stumbled over the inclusion of an "insulation area" in the recommended pcb layout:

recommended layout

I'm guessing this is supposed to prevent the contact springs from contacting any tracks under the socket. There are holes on the bottom through which this could conceivably happen.

  • Am I right in my assumption?
  • Is there something I should do to the layout in that area or will the solder resist suffice?
  • What does the Symbol in the green box mean?
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Am I right in my assumption?

The distance between the main contacts and outline of the contacts within the INSULATED is 2.7mm. The maximum pad length on a microSD is 1.6mm.

By specifying an area that must have resist, the chances of shorting is minimised

enter image description here

Is there something I should do to the layout in that area or will the solder resist suffice?

Resist should be fine but check tolerance stack up.

What does the Symbol in the green box mean?

That symbol is a mechanical drafting symbol for positional tolerance

3.4 LOCATION - Position tolerances are the most common location tolerance. Concentricity and symmetry are also types of location tolerances. Profile tolerances can be used to control location, but these are covered separately.
enter image description here
3.4.1 Position -The position tolerance symbol is a circle with a horizontal and vertical line drawn through the circle. See Figure 26.

[source: Drafting manual. Dimensioning and Tolerancing Symbols.]

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    \$\begingroup\$ I thought he was querying the symbol in the green box? \$\endgroup\$
    – user16222
    Jul 9, 2016 at 17:17
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    \$\begingroup\$ Missed that bit of the question. I think both were being asked about. \$\endgroup\$ Jul 9, 2016 at 17:17

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