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SMT electronics assembly manufacturing forum.


Question on Pad Size for ICT Test Points

#17122

Question on Pad Size for ICT Test Points | 7 August, 2001

Anyone have an idea on what the smallest feasible/reliable pad size and pitch should be for a PCB designed with an array of ICT test points?

Thanks in advance for your help.

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#17136

Question on Pad Size for ICT Test Points | 7 August, 2001

May be not directly to the point, but here's a start ... * Lands or vias: GT 40 thou for probing. Bonus => This provides LT 3 misses /1M hits. * Probe all points on one side of the board. Bonus => This lower fixture cost. * Test pads and vias: GT 25 thou from other land traces. * Small [LT 5 ohm] resistor measurements: Use two pads at each end and do 4-wire measurements. * Probes: Center selection drives cost. 50 thou centers [13 thou dia barrels] are about 5X the cost of 100 thou centers. Part of this cost is fragility of the lighter weight copper.

Pay me now or pay me later, eh?

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