## Electronics Forum: formula (Page 1 of 37)

### footprint formula

Electronics Forum | Thu Mar 02 09:13:07 EST 2000 | jacqueline Coia

Could anyone please tell me if there is a quick simple formula for working out the ideal SMD footprint for a 52 pin QFP using the dimensions specified on the manunfacturers component drawing. I know of the IPC 'SMD land patterns' standard, which I e

### footprint formula

Electronics Forum | Thu Mar 02 09:13:07 EST 2000 | jacqueline Coia

Could anyone please tell me if there is a quick simple formula for working out the ideal SMD footprint for a 52 pin QFP using the dimensions specified on the manunfacturers component drawing. I know of the IPC 'SMD land patterns' standard, which I e

### Re: footprint formula

Electronics Forum | Thu Mar 02 09:45:24 EST 2000 | Jacqueline Coia

Could this QFP be easily wave soldered if placed on solder side of PCB, if so are there two different footprint formulas that take both wavesoldering and reflow into consideration. Thanks again. Jack

### Re: footprint formula

Electronics Forum | Thu Mar 02 09:45:24 EST 2000 | Jacqueline Coia

Could this QFP be easily wave soldered if placed on solder side of PCB, if so are there two different footprint formulas that take both wavesoldering and reflow into consideration. Thanks again. Jack

### Component weight formula

Electronics Forum | Wed Mar 28 10:56:56 EST 2001 | jseagle

Does anyone know the formula for calculating the grams per sq cm of lead for mounting bottomside unglued components? Thanks James

### CM cost formula

Electronics Forum | Mon Feb 02 17:29:09 EST 2009 | diones

Hello all, I'd really like some input on devising a competitive cost formula for a new CM business in eastern Canada. If anyone has any experience or suggestions with this I would appreciate your comments. Thanks, Dion

### Re: footprint formula

Electronics Forum | Wed Mar 08 21:11:41 EST 2000 | Dave F

Jack: I'll think about the latter point over my next McEwan's. Dave F

### Re: footprint formula

Electronics Forum | Wed Mar 08 21:11:41 EST 2000 | Dave F

Jack: I'll think about the latter point over my next McEwan's. Dave F

### Component weight formula

Electronics Forum | Wed Mar 28 13:45:45 EST 2001 | gcs

sorry, equal to or less than.

### Re: footprint formula

Electronics Forum | Wed Mar 08 21:16:38 EST 2000 | Dave F

Wolfgang: I agree that the IPC pads are reflow / top side wave solder. We run bottom-side PCLL at 45� to the wave with fairly involved solder thieves. Ta. Dave F

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