Low power, high resolution CMOS variable-delay element

This letter proposes a novel CMOS variable-delay element (VDE). It employs a RC-based differentiator to control the pMOS transistor of a CMOS inverter, whose delay time becomes dependent on the time constant RC. By implementing the RC differentiator with transistor components, the delay can be controlled by variations of both R and C, for fine and coarse delay tuning, respectively. Simulated results show good delay linearity, high resolution and low power consumption for the proposed circuit.