An Inductorless 20-Gbaud Overshoot Suppression Modulator Driver Using Interleave Frequency Variant Feedback in 90-nm CMOS

inductorless modulator driver with effective overshoot suppression and a large swing for high-speed optical communications is presented. A novel interleave frequency vari-ant feedback (IFVF) technique is proposed, which employs active feedback loops with the RC degeneration. The RC degeneration allows place the pole in the overall transfer function to shape the waveform for overshoot and ringing suppression. Using a 90-nm complementary metal oxide semiconductor (CMOS) technology, the driver achieves a maximum 3.4 V-pp differential output voltage swing. Clear eye diagrams for non-return to zero (NRZ) and pulse amplitude modulation 4-level (PAM4) signal formats can be obtained up to 32 Gb/s and 20 Gbaud, respectively. The circuit consumes a total power of 560 mW and occupies a core area of only 0.092 mm(2).