This paper presents the low power architecture and design techniques for the mobile handset LSI Medity M2. M2 is a second-generation mobile handset LSI which integrates a Digital baseband and Application processor on a chip. M2 is capable of supporting 3.2 Mbps HSDPA, WCDMA communications, and rich, high-resolution multimedia applications, while power consumption is kept almost the same as in its predecessor chip M1. To reduce power consumption, M2 adopts hardware management clock control schemes, Multiple Vt transistors, an On-chip Power Switch, and Back-bias control. Preliminary measurement results show the design to work very well.