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

An inductorless modulator driver with effective overshoot suppression and a large swing for high-speed optical communications is presented. A novel interleave frequency variant 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 Vpp 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 mm2.