1LIMMS, CNRS-IIS, University of Tokyo, Meguro, Tokyo, Japan
2ENSIEG-INPG, Grenoble, France
3Ecole Superieure d''Ingenieurs en Electrotechnique et Electronique, Groupe ESIEE, Noisy le Grand, France
4Kanagawa Industrial Technology Research Institute, Ebina, Kanagawa, Japan
5VLSI Design and Education Center, University of Tokyo, Japan