An optimization approach to designing OTAs for low-voltage sigma-delta modulators

Author

Lampinen, Harri ; Vainio, Olli

Author_Institution

Digital & Comput. Syst. Lab., Tampere Univ. of Technol., Finland

Volume

2

fYear

2000

fDate

2000

Firstpage

1066

Abstract

High performance OTA (Operational Transconductance Amplifier) structures for high-speed, low-voltage, switched-capacitor based sigma-delta modulator applications have been designed utilizing an efficient circuit optimization strategy presented in this paper. The main idea is to use external programs together with a circuit optimizer to construct flexible optimization algorithms. Optimization goals and constraints are derived from analytical equations and application requirements. Using a 0.35 μm CMOS processing technology a CFCFC (Complementary Folded Cascode Feedforward Compensated) OTA with 2.5 V supply obtained 470 MHz unity-gain frequency, 350 V/μs slew rate, over 74 dB gain, and over 70° phase margin using 10 pF load capacitances

Keywords

CMOS integrated circuits; circuit CAD; circuit optimisation; integrated circuit design; modulators; operational amplifiers; sigma-delta modulation; switched capacitor networks; 0.35 μm CMOS; 0.35 mum; 10 pF; 10 pF load capacitances; 2.5 V supply; 470 MHz; 470 MHz unity-gain frequency; 74 dB; 74 dB gain; Complementary Folded Cascode Feedforward Compensated OTA; LV modulator; Operational Transconductance Amplifier; high-speed modulator; low-voltage sigma-delta modulators; optimization algorithms; switched-capacitor sigma-delta modulator; CMOS technology; Circuit optimization; Constraint optimization; Delta-sigma modulation; Design optimization; Equations; Flexible printed circuits; Operational amplifiers; Switching circuits; Transconductance;

fLanguage

English

Publisher

ieee

Conference_Titel

Instrumentation and Measurement Technology Conference, 2000. IMTC 2000. Proceedings of the 17th IEEE

Conference_Location

Baltimore, MD

ISSN

1091-5281

Print_ISBN

0-7803-5890-2

Type

conf

DOI

10.1109/IMTC.2000.848904

Filename

848904