A Si bipolar phase and frequency detector IC for clock extractionup to 8 Gb/s

A phase and frequency detector IC is presented that operates up to an NRZ bit rate of 8 Gb/s. The IC comprises a phase detector (PD), a quadrature phase detector (QPD), and frequency detector (FD). In the PD and QPD the VCO signal and the quadrature VCO signal are sampled by the NRZ input signal. The two beat notes provided by this operation are subsequently processed in the FD. The superposition of the FD output and the PD output signals are then fed into a passive loop filter (lag/lead filter). The loop filter and the VCO are external components. The measured pull-in range is >±100 MHz at 8 Gb/s. The measured r.m.s. time jitter of the extracted clock is less than 1.9 ps for a pseudorandom bit sequence (PRBS) length of 2²³-1. A 0.9-μm 12-GHz f_T silicon bipolar process was used to fabricate the chip with a total power consumption of 1.4 W