Hey All,

I have chosen the MIC3385 to do a 1.9V rail for my design, but am a bit confused by the "SW" pins (see datasheet in URL). My best guess is that these are to allow for 'external' inductor operation? Perhaps some applications want to have negligible ripple and thus need a bigger inductor than that internal?

http://www.micrel.com/_PDF/mic3385.pdf

Cheers,

James

 

My best guess is that these are to allow for 'external' inductor operation?

Yep - makes sense to me. It's confusing that the explicit intent of the design is the benefit of eliminating the need for an external inductor (there's already a 0.47uH inside). Perhaps it does have something to do with improving performance with an external inductance - but then you have the caveat that there will be issues with the switching noise at that node if you intend to use it in that way.