In many digital designs there is a need to use multi-stage tapered buffers to drive large capacitive loads. These buffers contribute a significant percentage of overall power. In this thesis, we propose two novel tunable buffer designs that enable reduction in power in the presence of process variation. A strategy to derive the optimal buffer size and the optimal tuning rule in post-silicon phase is developed. By comparing several tunable buffer circuit topologies, we also demonstrate the tradeoffs in tunable buffer topology selection as a function of switching activity, timing requirements, and the magnitude of process variations. Using HSPICE simulations based on the high performance 32nm ASU Predictive Model, we show that up to 30% average power reduction can be achieved for a SRAM word-line decoder while maintaining the same timing yield. / text