Analysis, Comparison, and Experimental Validation of a Class AB Voltage Follower With Enhanced Bandwidth and Slew Rate

This paper describes a bandwidth (BW)- and slew rate (SR)-enhanced class AB voltage follower (VF). A thorough small signal analysis of the proposed and a state-of-the-art AB-enhanced VF is presented to compare their performance. The proposed circuit has 50-MHz BW, 19.5-V/<inline-formula> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> SR, and a BW figure of merit of 41.6 (MHz <inline-formula> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> pF/<inline-formula> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula>) for <inline-formula> <tex-math notation="LaTeX">$C_{L} = 50$ </tex-math></inline-formula> pF. It provides 13 times higher current efficiency and 15 times higher BW than the conventional VF with equal 60-<inline-formula> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> static power dissipation. The experimental and simulation results of a fabricated test chip in the 130-nm CMOS technology validate the proposed circuit.

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