h29_lecture21_2

h29_lecture21_2 - Lecture 21 OTA Variants CMFB...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
EE 214 Lecture 21 (HO#29) B. Murmann 1 Lecture 21 OTA Variants CMFB Implementation Examples Boris Murmann Stanford University murmann@stanford.edu Copyright © 2004 by Boris Murmann EE 214 Lecture 21 (HO#29) B. Murmann 2 Overview Reading – 12.5 (CMFB Circuits) – 12.6 (Fully Differential Amplifiers) – 9.4.4 (Compensation of Single Stage CMOS OTAs) Introduction – Today's lecture surveys common OTA architectures and associated implementation aspects. Most OTAs used in practice are derivatives of the basic single- or two-stage topology, with add-ons such as simple cascodes or gain boosted cascodes. The survey concludes with a brief analysis of the most commonly used common mode feedback implementations.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
EE 214 Lecture 21 (HO#29) B. Murmann 3 Telescopic OTA Approximately same gain as two stage amplifier, with only two current legs – Maximum power efficiency Issue: Low swing – Especially if input and output common mode cannot be chosen freely EE 214 Lecture 21 (HO#29) B. Murmann 4 Biasing Typically use at least 20% of tail current in auxiliary biasing branch – Must avoid slow recovery of this node during transients Can use several device in series to implement M B1 –" 1 / 3 rd or 1/5 th" device – Helps avoid extremely small width for M B1 M B1 M B2 1.2 I TAIL 0.2 I TAIL
Background image of page 2
EE 214 Lecture 21 (HO#29) B. Murmann 5 Folded Cascode OTA Large input common mode rage
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 10

h29_lecture21_2 - Lecture 21 OTA Variants CMFB...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online