Through holes

First, SM-782 elates to surface mount pads. So, expecting to find PTH design rules there is a bit of a stretch.

Search the fine SMTnet Archives for similar threads. For instance here�s one from last week: http://www.smtnet.com//forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=5096&#Message19709&

Additionally, �DFM For Through-Hole Technology� [Vivek Sharma, Printed Circuit Design, 1/01, p 14-20] is a good general point of reference.

Finally, 2221, 8.3.1 Leads Mounted In Through-Holes says, �Requirements for lead-to-hole relationships are detailed in 9.2.3 through 9.3 of the related design sectional.� This makes sense because you�d expect that relationship to change according to the type of board [ie, rigid organic, flexible, etc].

As an example, 2222, Table 9-4 Plated-Through Hole Aspect Ratio has the information you seek for rigid organic boards. Leading-up to that table, 2222 goes into a rather involved discussion on the proper gap between lead and hole according to product class. This is too burdensome to discuss here and not knowing the type of board you�re designing or the equipment class could be a waste of time anywho.

Consider obtaining the section design standard for the type of board you are designing to compliment and expand on 2221.

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