Hi Alejandro,
 
it may turn out that HASL is not the best choice for this application. With
this pitch and lower we love to have a more planar surface.
We had enough trouble with 0.8mm pitch and concave termination in the
beginning and a lot of pad-tuning had to be done. It turned out that the
manufacturer´s recommendations weren´t that bad at all (exept for the
excessive length of the pad, must have been for wavesoldering I guess).
Don´t think that a stepped stencil is necessary, it would make life more
complicated than necessary. Better control the amount of paste with the
aperture size.
 
Would be nice to have a test board with different layouts for that purpose,
wouldn´t it?
 
Good luck 
 
Wolfgang

-----Ursprüngliche Nachricht-----
Von: Becerra Alejandro [mailto:[log in to unmask]]
Gesendet am: Mittwoch, 14. November 2001 15:42
An: [log in to unmask]
Betreff: [TN] Resistor Networks of 0.5 mm Pitch


Hello to All, 
we are planning to start using resistor networks of 0.5 mm pitch 
in a normal reflow soldering process. The boards are FR-4 with HASL coating.

Is there any special concern about this component? 
So far the smallest resistor network that we are using is a 0.8 mm pitch. 
Within my company it is being recommended a stepped stencil for this
component. Is this necessary? 

Thanks, 

Alejandro Becerra 

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