4-ch 25-Gb/s Small and Low-power VCSEL Driver Circuit with Unbalanced CML in 65-nm CMOS

A 4-channel 25-Gb/s VCSEL driver circuit in a 65nm CMOS with a small chip area and low power consumption is presented. The proposed circuit employs an inductor-less bandwidth enhancement based on feedback topology and an unbalanced current mode logic driver core to reduce power consumption. We designed and fabricated the proposed 4-channel driver circuit in a 65-nm CMOS technology. The proposed circuit achieves about half of the power consumption and chip area of the conventional one.