Degree Type

Thesis

Date of Award

2009

Degree Name

Master of Science

Department

Electrical and Computer Engineering

First Advisor

Degang J. Chen

Abstract

The need for high bandwidth operational amplifiers (op amp) exists for numerous applications. This need requires research in the area of Op Amp bandwidth extension. The exploited method in this thesis uses a class of compensation called Indirect Feedback Frequency Compensation in which the compensation current is fed back indirectly from the output to an internal high impedance node, to extend the bandwidth of an Op Amp.

Among various compensation methods for operational amplifiers, indirect compensation offers potentially large benefits in regards to power to speed trade-off. The indirect compensated Op Amps can exhibit significant improvements in speed over traditional Miller compensated Op Amps and result in much smaller layout size and lower power consumption. However the technique has not been widely used in practice due to a lack of clear design procedure. This thesis develops an analytical description of how indirect compensation works and derives key trade off equations among various specifications. These results provide the insight needed for practically designing operational amplifiers with this technique. Based on the results, a step-by-step design procedure is proposed for an operational amplifier using indirect compensation. To demonstrate the proposed design procedure, a two stage Op Amp is designed. The Op Amp achieved a 2 MHz gain-bandwidth

product (GBW) driving a large capacitive load (100 pF). The GBW of the Op Amp was improved by a factor of 10 times compared to the miller compensation scheme. The amplifier documented in this thesis achieved a higher simulated figures-of-merit (FoMs) compared to the state-of-art and can be directly used in integrated systems to achieve higher performance.

DOI

https://doi.org/10.31274/etd-180810-1663

Copyright Owner

Vaibhav Kumar

Language

en

Date Available

2012-04-30

File Format

application/pdf

File Size

76 pages

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