The 3DS was similar but actually used yet another type of connector. It's very common to find aftermarket chargers that have a USB-A on one end and a split dual DS+3DS connector on the other.

Both generations of console technically take 4.6v and not 5v, but in practice it doesn't matter. That may be why Nintendo didn't just make it micro USB directly (or why they never sold an official USB-A charger for the DS/3DS, only ever wall-wart) though.