In conjunction with crunching down power consumption figures, system designers also need to find ways to squeeze down the size of the system designs if they are able to meet the stringent demands for new products with increased performance and reliability. Achieving a small product footprint is desirable because the smaller the device, the less expensive it is likely to be in terms of material, PCB requirements, storage, and manufacturing. This also has a massive impact on market take up and profitability. For example, in the United States alone, the annual energy consumption of the installed set-top boxes is over 20 TW-h. The main processor, the power supply, and the RF front-end are the circuit blocks that have the highest effect in total system power consumption. Reduction in this level of energy consumption is critical to support the market needs and trends. The magnitude of this number, combined with the increasing popularity of set-top boxes, has driven many energy-efficiency initiatives over the last few years, both in the US and worldwide.