Distributed Active Decoupling Capacitors for On-Chip Supply Noise Cancellation in Digital VLSI Circuits

A distributed active decoupling capacitor (decap) circuit is proposed to suppress the on-chip power supply noise in digital VLSI circuits. Effectiveness on suppressing local supply noise is verified from a 0.18mum test chip using multiple on-chip supply noise generators and supply noise sensors. Measurements show 4-11times boost in decap value over conventional passive decaps for frequencies up to 1 Hz. Decap area reduction of 40% is achieved