A transconductance enhancement technique for bulk-driven OTAs working in weak inversion

Abstract

A proposed transconductance enhancement technique for bulkdriven OTAs working in weak inversion is presented in this paper. The basic idea is to use a bulk-driven input differential pair employing the auxiliary amplifier and positive feedback technique to enhance transconductance, which improves the enhancement ratio of transconductance from (n + 1)/ (n − 1) to (n + 2)/(n − 1). The proposed amplifier based on the mentioned technique is simulated on UMC 180 nm process with the help of Spectre. The simulation results demonstrate that the transconductance of the bulk-driven OTAs working in weak inversion improves almost 50% with just a little increased power consumption compared to the conventional counterparts.

Compensation of G m ‐C lossless integrator for finite output resistance

“…Typical value of g mc considering R o1 = 1 MΩ, C 1 = 15.915 pF, C o1 = 0.1 pF, and ω = 2 × π × 5 × 10 5 rad/s, we obtain g mc = 2.484 m℧. Thus, the needed high transconductance can be realised using the solutions available in the literature [12][13][14][15][16].…”

Floating-bulk transistors: An alternative design technique for CMOS low-voltage analog circuits

“…Quasi-floating gate requires a high value resistor, R Large , typically implemented by a single transistor connected to a DC biasing voltage and a capacitor, C i , connected to the AC input voltage in order to work properly. Low voltage analog circuits have been widely improved by using these Bulk Driven [4,5,6,7,8,9,10,11,12,13,14,15,16] and Floating Gate [17,18,19,20,21,22,23,24,25,26,27,28,29,30] techniques, and from them we derive the new technique presented in following section.…”