From IPC-6012B Class 3/A - Performance Specification Sheet for Space and
Military Avionics, exception to IPC-6012B Annular Ring Requirement(s): 3.4.2
& 3.6.2.9

Unsupported holes - 0.38 mm [0.015 in] minimum

Internal/External Plated-Through Holes - 0.051 mm [0.002 in] minimum allow
20%reduction unless already at 0.051 mm [0.002 in]

Regards,

Bob


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: Tuesday, May 03, 2005 12:56 PM
To: [log in to unmask]
Subject: [TN] Annular ring:- What should we sign up for ????

We have a tough brd to manu. and want to know what kind of annular ring
requirement should we sign up for.

This is for SPACE so it requires IPC-6012 class 3, w/ exceptions to  annular
ring.

12 layers

1)  Burried vias 7-11
2)  Burried vias 6-11
3)  Blind vias  6-12

4)  Burried and blind vias have 16 mill pads for vias  (thickness  ~ 60
mils)

5)  Thru holes (~90 mils)  18 mil pads.

6) Cavity brds w/ broad side coupled diff. impedance control

Thanks for your help in advance

Rush
[log in to unmask] (mailto:[log in to unmask])
818-768-3919

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