how to create a j-lead pcb lib from datasheet without pad size info

Thread Starter

johnny411

Joined Mar 3, 2020
27
i have created quite a few pcb librarys before from datasheets, however i have never created (or used) a j-lead one before. i have absolutely no idea what pad size it should be, and the datasheet does not tell me. it seems to be in dip 14 with J-lead.

dimensions 8l61.PNG


here is a link to the datasheet: https://www.cotorelay.com/wp-content/uploads/2014/09/8L_series_reed_relay_datasheet1.pdf
device: 8L61-05-001
digikey: https://www.digikey.com/product-detail/en/coto-technology/8L61-05-001/306-1271-ND/1914965

what i want to know is what pad size i should use and is there a standard? better yet if someone has the library for this (or similar), but all i really need is the pad size. thanks.
 

Thread Starter

johnny411

Joined Mar 3, 2020
27
ok so here is what i came up with. the pads are the recommended oval size from a dip package turned into rectangle. i think they look about right, but i dont know.


relay pcb size.PNG
 

jpanhalt

Joined Jan 18, 2008
9,434
Without dimensions, it is hard to advise. Are you reflow or hand soldering? If hand soldering, I would make the pad extend a little past the outside edge of the J so you can get a small tip to touch the pad and lead at the same time. I would add about 30 mil on each side, so outside pad to outside pad ~ 420 mil, if you have room. If space were tight, I would still go outside the loop but maybe by only 15 to 20 mil. As for the inside dimensions, I would be sure the pad covered the width of the loop in the J. Having solder resist under any part of the J could interfere with solder flow.

For reflow soldering, the extension outside the loop is less important, but I would still have the pad as large as the loop or slightly larger,
 

Thread Starter

johnny411

Joined Mar 3, 2020
27
Without dimensions, it is hard to advise. Are you reflow or hand soldering? If hand soldering, I would make the pad extend a ...
thanks. i am reflow soldering as there is no way i could hand solder some of the small 0402 components in this density. i also have no idea what the size of the J is.

here is a pic of the unfinished layout. it is 4 layer double sided and still barely enoughph room (i want as little as possible on bottom) and still a pile of components to fit. the regulators very specific capacitor requirements just kill the space:

analog front unfinished.PNG
 

Janis59

Joined Aug 21, 2017
1,181
I am always trying to not believe on preset libraries. I like the paches are more wide and strongly more long. So I like to acknew the body size as the first thing. Then set the coordinate size to the corresponding mm or inch base and draw with the white line the corpus four-angle. Then adapt the coordinate mesh according the step of leads as the second thing. Inch scale or mm scale and set the one step identical or double identical to the step. Make the patch size definition according your will and copy and paste every next or over-one-next position using auto-landing activated. It never will allow to land the patch in wrong place. Then apply the panel of "set like a unity". This will not allow to harm one or other patch in later redaction.
 
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