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what is back drilling and why is it preffered?

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v_kumar

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what is back drilling

what is back drilling and why is it preffered.

thanks
 

majnoon

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Re: Back drilling

It is a process to remove the unused section of plated through holes.
This will ensure signal stubs are minimized; Stubs are the source of impedance discontinuities and signal reflections which become more critical as data rates increase. It is preferred method in HS designs.

Allegro handles back drilling processes.

Regards,

M
 

v_kumar

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Back drilling

Why should we go for back drilling and not for blind and burried vias because the end result is the same minimizing stub.

Thanks
 

vengat

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Re: Back drilling

v_kumar said:
Why should we go for back drilling and not for blind and burried vias because the end result is the same minimizing stub.

Thanks


Hi V_kumar,

Main Purpose of Back drilling is Signal Reflection and Reduce the Stub,
we can do back drilling or Blind or Burried Vias,
when we go for Blind or burried via,manufacturing cost will increase

thanks
Vengat T
 

Scottm

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Re: Back drilling

Another reason for backdrilling instead of using blind and buried is if you are using it in a backplane, you most likely will not have many vias as you will be going from connector to connector so you would be backdrilling the connector pins which wouldn't be blind or buried.

cheers

Scott
 

v_kumar

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Back drilling

If we backdrill the connector pins than how can we solder it from the other side since it is a PTH connector. can you upload any pic for this to make clear pitcher

What are the files to be sent to manufacturer to do the back drilling.
 

Scottm

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Re: Back drilling

in the designs i was talking about we use press-fit connectors so no soldering required. The files we typically send are just modified drill files that give the coordinates of the holes to be back drilled they also include the a fab drawing with the depth of each drill required.
 

    v_kumar

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