SMD resistor arrays, concave or convex terminals

[[email protected]]

Can't find any reason for having two different terminal styles in the
data sheets. What's the story here? Concave would seem easier to pick-
and-place manually IMO.

 

[Klaus Kragelund]

Can't find any reason for having two different terminal styles in the
data sheets. What's the story here? Concave would seem easier to pick-
and-place manually IMO.

Hi

I did some work on this almost 10 years ago and introduced them at the
place I worked. They can relly save a lot in production price, but we
have had very much trouble getting the production up to speed of
mounting them without solder errors. As far as I know they never
succeeded in reducing the failure rate to a satisfactory level. But,
thats a long time ago, probably better now and perpaps your production
have more experience.

We used the convex version from phycomp, since the purchase department
reported that this was the dominant one used in the marked and thus
had some advantages. (ARV341). We had major problems in finding the
correct stensil thickness and footprint, did a lot of thermal cycling
tests. If you want, I think I can dig up some data?

Regards

Klaus

 

[linnix]

Can't find any reason for having two different terminal styles in the
data sheets. What's the story here? Concave would seem easier to pick-
and-place manually IMO.

I think the convex one works like pins, so easier to manually solder.
Concave works better with auto pick and place. If you are not sure,
you can always try the flat one (choice #3).

 

[[email protected]]

We used the convex version

Thanks, I've been using the convex version for the past two years
without difficulties. Probably chose convex because of availability at
the time.

 

[[email protected]]

If you are not sure, you can always try the flat one (choice #3)

Flat is out of the question, poor availability in the size I need.
Probably continue to use convex since that's the cheapest option at
the moment but can use either concave or convex. Thanks!