Multistage operational transconductance amplifier frequency compensation technique based on fully differential feedback stage

Abstract

In this article, a new configuration of a three-stage Complementary metaloxide-semiconductor (CMOS) operational transconductance amplifier (OTA) isproposed. It removes the feedforward path while simultaneously amplifying the feedback path in the compensation network. Also, the proposed circuit uses only one small compensation capacitor which makes it appropriate regarding die area. The approach behind is demonstrated through a successful design using 0.18-μm CMOS technology. In fact, the simulated OTA shows better performance in comparison with other methods and achieved 20.2 MHz, 82 , and 124 dB as gain-bandwidth product, phase margin, and DC gain, respectively, and consumes 545 μW @ 1.8 V. K E Y W O R D S

Multi‐Stage CMOS OTA Frequency Compensation: Genetic algorithm approach

“…Equation (21) highlights the small-signal operation of the amplifier by including the GBW frequency, which is a general factor used to categorize amplifiers. Those amplifiers that drive large load capacitors and consume less power are more desirable.…”

“…For instance, AC boosting compensation (ACBC) [2], active feedback frequency compensation (AFFC) [3], and differential feedback path (DFP) [7] have been introduced to enhance amplifier parameters compared with basic NMC and RNMC approaches. Commercial tendencies have led to even more complicated amplifiers to satisfy speed and power demands [18][19][20][21][22][23][24][25][26][27][28][29]. For instance, Ref.…”

Five‐stage CMOS OTAfrequency compensated via nested differential feedback

“…The major part of methods is related to three‐stage amplifiers while four‐stage cases are highlighted recently for their high DC gain. Logically, more nodes in amplifier leads to more complicated compensation network 18–26 . So, design simplicity attracts attention since complex structures are less reliable for many reasons such as fabrication mismatches and heavy theoretical calculations.…”

“…Logically, more nodes in amplifier leads to more complicated compensation network. [18][19][20][21][22][23][24][25][26] So, design simplicity attracts attention since complex structures are less reliable for many reasons such as fabrication mismatches and heavy theoretical calculations. In this regard, in this paper a five stage transconductance amplifier with related compensation network is proposed, described and simulated.…”