TSB81BA3 PINS NOT IN ZAJ PACKAGE

Hi John,

For another device w/similar BGA package (likely true in this case as well):

With reference to the ZQW113 (BGA) package for the F2618 we usually recommend that any reserved or unused balls be connected to GND. I think it serves 2 purposes 1) connecting these balls to the board provides better mechanical stability and 2) the unused balls are likely electrically connected to each other via the substrate so the recommendation is not to leave them floating (switching noise could couple from other balls).

I'll ask the spps folks for this device to comment.

Hi Jeff,

Thanks for those details.  I am a little surprised, but my experience has been in the past that if the manufacturer didn't define a pin in the data sheet then don't make a connection to it.  The reason being is that some undefined pins were used by the manufacturer for production testing.  In the case of mechanical stability it is possible to put a pad down for a ball to be soldered to without connecting the pad to a signal or a power plane.  I don't see how connecting a pad to a signal or plane makes the mechanical connection between the board and device any better.  Adding a connection to a plan could improve heat conduction into board though.

In any case, I want to direct the customer to do what TI recommends so lets see what the apps folks have to say.

Thanks for your help.

Regards,

John   

I was a bit surprised as well but this advice came from BU Apps. for that other device in a BGA pkg. I'm "polling" the specific BU Apps. person for this device....stay tuned....