A Novel Fast-Switching 5-GHz Phase-Interpolator with Superior Linearity in 65-nm CMOS Technology

This paper presents a fast-switching phase-interpolator (PI) operating at 5-GHz with superior linearity. The PI is designed for high bandwidth clock and data recovery (CDR) to enable high jitter-tolerance (JTOL) in serial-link applications. It is based on a current-switching topology to enable a high phase-update rate. It also employs an adaptive regenerative amplifier (ARA) to prevent amplitude-dependent delays. This PI consists of cascaded trigonometric phase-interpolator (TPI) and linear phase-interpolator (LPI) stages together with cross-coupled devices load to immensely enhance its linearity, enabling an 8-bit resolution with an integral nonlinearity (INL) of 0.5 LSB and differential nonlinearity (DNL) of 0.15 LSB. The PI is implemented in 65-nm CMOS technology, operating under a 1.2 V supply with a current consumption of 26mA.