Dear Hernefjord Ingemar,

sorry I will reframe my qustion briefly.

Basically we are in packaging ,Presently we are doing the bga package,
we are already choosen the number of io's.but how many pins or balls to be 
provided for power and ground signals.actually our die consumes 2 amp 
current.

For 1 amp current one pin is sufficent. or can you guide me on this.

Thanks &Regards
Madhusudhan Kulkarni


----- Original Message ----- 
From: "Hernefjord Ingemar" <[log in to unmask]>
To: "TechNet E-Mail Forum" <[log in to unmask]>; "Madhusudhan Kulkarni" 
<[log in to unmask]>
Sent: Thursday, February 15, 2007 12:47 PM
Subject: RE: [TN] BGA ball current


>
> Madhusudhan,
>
>
> I happened to get same question recently, my opinion is this:
>
>
> The current limitation is not the balls, but the bondwires and the
> copper lines from balls to chip. The current capacity of bond wires is:
>
>
>
> I =  sq root(K/2P) x (Pi x D exp2/L)  x  sq root Delta T
>
> Where
>
> I = current in amperes
> K = thermal conductivity in Watts/cm/Centigrade
> P = resistivity in Ohm/cm
> D = diameter of wire in cm
> L = length of wire in cm
> Delta T = temperature rise in Centigrades
>
> Thus, a "normal" 0.001 inch (25um) gold bond wire will be able to carry
> 0.22 amperes. Just an example.
>
> But noone designs a 25um BGA bond wire for such constantly high current.
> At least what I think. Intermittantly, no problems, a 25um gold bond
> wire can withstand 5 amperes during some milliseconds.
>
> Likewise, you can calculate the current capacity for the balls, which
> ought to have a magnitude higher current capacity.
>
> Inge
>
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Madhusudhan Kulkarni
> Sent: den 15 februari 2007 04:43
> To: [log in to unmask]
> Subject: [TN] BGA ball current
>
> Hi,
>
> what is the current rating of BGA ball(standard ball sizes).
>
> Regards
> Madhusudhan Kulkarni
>
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