One of today's most successful embedded devices, the mobile phone, embodies a set of challenging design requirements: long battery life, small size, high performance and low cost. The single parameter that complicates the simultaneous fulfilment of all of these design goals is energy efficiency of the system, since batteries only hold a finite amount of charge. To operate within the allotted energy budget, systems must be optimized for energy consumption during design and also at run-time. Increasingly it is not sufficient to statically optimize for worst-case conditions but designers must enable systems to adapt to conditions at runtime. The Intelligent Energy ManagerTM (IEM) technology provides an integrated solution for addressing energy management of SoC devices. In this paper we present data about the energy consumption characteristics of a multiple power-domain based SoC which includes PDA functionality built around an ARM926EJ-S core.