A fully differential amplifier with CMOS feedback biasing for sensing CMUT signals

Author

Bose, Soumya ; Mandal, Pradip

Author_Institution

India Design Center, Rambus Inc., Bangalore, India

fYear

2014

fDate

Feb. 28 2014-March 2 2014

Firstpage

159

Lastpage

163

Abstract

The paper illustrates design of a fully differential amplifier to sense current signals generated by CMUT for ultrasound imaging. Detection of reflected ultrasonic waves from body tissues requires low noise amplifier with wide input dynamic range. The transducer, being capacitive, isolates dc voltage from the input of the amplifier necessitating additional biasing circuit. In this work, a differential amplifier topology is chosen for its ability to reject common mode interference. Biasing is done by low frequency feedback using CMOS transistors which do not add significant noise to the system. The amplifier is designed in 0.18 μm CMOS process. Its input referred noise is 24.3 μV rms in the band 1-15 MHz. At 10 MHz it provides a gain of 25.5 dB with an input dynamic range of 62.5 dB. The amplifier consumes 314 μW of power with 1.8V-GND supply.

Keywords

CMOS analogue integrated circuits; biological tissues; biomedical electronics; biomedical imaging; capacitive sensors; circuit feedback; differential amplifiers; low noise amplifiers; microsensors; ultrasonic imaging; ultrasonic transducers; CMOS feedback biasing circuit; CMOS transistors; body tissues; capacitive micromachined ultrasonic transducer; common mode interference rejection; differential amplifier topology; frequency 1 MHz to 15 MHz; fully differential amplifier; gain 25.5 dB; isolates dc voltage; low frequency feedback; low noise amplifier; power 314 muW; reflected ultrasonic wave detection; sensing CMUT signals; size 0.18 mum; ultrasound imaging; voltage 1.8 V; voltage 24.3 muV; wide input dynamic range; Acoustics; CMOS integrated circuits; Gain; Logic gates; Noise; Sensors; Transistors;

fLanguage

English

Publisher

ieee

Conference_Titel

Students' Technology Symposium (TechSym), 2014 IEEE

Conference_Location

Kharagpur

Print_ISBN

978-1-4799-2607-7

Type

conf

DOI

10.1109/TechSym.2014.6807933

Filename

6807933