Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Frank

#11154

measuring pitch | 7 June, 1999

I was wondering what measurements are used to define pitch?

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John Thorup

#11155

Re: measuring pitch | 7 June, 1999

| I was wondering what measurements are used to define pitch? Generally we would use it for the distance from lead center to lead center of an IC. For instance, an SOIC would usually have a pitch of 0.050" or 50 thousandths of an inch (1.27mm)|

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#11156

Re: measuring pitch | 7 June, 1999

| I was wondering what measurements are used to define pitch? | Frank: John's correct with the most common definition, but there can be others, depending on your perspective. TTYL Dave F

Pitch. The center-to-center spacing between the (1) leads of a component, (2) pockets on a carrier tape, or (3) two adjacent sprocket holes. (4) The nominal distance between the centers of adjacent features or traces on any layer of a printed circuit board.

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Frank

#11157

Re: measuring pitch | 7 June, 1999

Thanks for the clarification! So in generic settings what are the normally the components with the smallest pitch? Will a machine with 20 mil capability handle almost anything?

| | I was wondering what measurements are used to define pitch? | | | Frank: John's correct with the most common definition, but there can be others, depending on your perspective. TTYL Dave F | | Pitch. The center-to-center spacing between the (1) leads of a component, (2) pockets on a carrier tape, or (3) two adjacent sprocket holes. (4) The nominal distance between the centers of adjacent features or traces on any layer of a printed circuit board. |

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#11158

Re: measuring pitch | 7 June, 1999

| | | I was wondering what measurements are used to define pitch? | | | | | Frank: John's correct with the most common definition, but there can be others, depending on your perspective. TTYL Dave F | | | | Pitch. The center-to-center spacing between the (1) leads of a component, (2) pockets on a carrier tape, or (3) two adjacent sprocket holes. (4) The nominal distance between the centers of adjacent features or traces on any layer of a printed circuit board. | | | | | Thanks for the clarification! So in generic settings what are the normally the components with the smallest pitch? Will a machine with 20 mil capability handle almost anything? | Frank:

1 For non-array components; the more complicated the function of the compoent, the more likely it will have a finer pitch than a component that is less complex. So I'd expect a TSOPs and a 208 lead QFPs to have finer pitch than a resistor array. If that is't too generic. 2 Machines that can handle 20 pitch can usually handle the more coarse pitches.

TTYL

Dave F

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