Loss-Compensated Cascaded Multistage Distributed Power Amplifier in 65nm CMOS Technology

Abstract

This work presents the analysis, design, and implementation of a fully integrated loss-compensated cascaded multistage distributed amplifier (LC-CMSDA) in $65nm$ CMOS technology. The proposed LC-CMSDA consists of three distributed stages in cascade configuration. The input stage utilizes three gain-cells in a distributive topology and offers 10 dB of gain. The second stage deploys two-sections while the output stage has three gain-sections in a distributive configuration. The interstage artificial lines are tapered towards large gain and high output power. Interstage inductive peaking in the gain-cell and high frequency loss-compensation at the gate of the cascode, extend the bandwidth. The RF chokes of all three stages have been realized on-chip that leads to a fully integrated design. Small-signal measurement results demonstrate measured peak gain of 21.5 dB and minimum gain of 9 dB through 50GHz of bandwith, resulting into a 146 GHz gain-bandwidth product. Large-signal characterization show peak saturated output power of 14.93 dBm with a peak drain efficiency of 8.95%. The third-order intercept point is better than 15 dBm. The proposed LC-CMSDA occupies only an area of $1.33~mm^{2}$ .

Keywords

• Distributed amplifier
• dual-feed
• active-split
• capacitive compensation
• split-drain line