Dear Patrick Tussey,

For passive components (tantalum capacitors, chip resistors, etc.), Hollomon
says

"Standoff height typically between 0.05 mm / 0.002 inch and 0.102 mm / 0.004
inch ... proper design ... right amount of solder."
-- p. 403; see also p. 89.
_Surface-Mount Technology for PC Boards_ by James K. Hollomon, Jr. (1995) ISBN
0-7906-1060-4

There's a little picture showing that too much solder lifts the component
higher, and (as you might expect) too little solder  lets the component rest
closer to the board. (But, of couse, no closer than the 0.0014 inch thickness of
the 1 ounce copper lands).

I suppose I would expect heavier parts to normally sink even closer to the board
than these passives.

[log in to unmask] on 2000-12-13 12:07:30 PM


I've been asked if I can evaluate and identify the amount a part will float in
the 'z' direction during reflow solder. We are using a small surface mount
connector in a phone application and the z axis must be very tightly controlled
for mating purposes. Anyone have any ideas where to find information on this
topic?

Thanks in advance,

Patrick Tussey
Hughes Network Systems

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