CMOS Technology Characterization for Analog and RF Design

Author : Behzad RazaviPresenter : Kyungjin Yoo

Index

I. IntroductionII. Motivation and IssuesIII. Characterization for analog designIV. Characterization for RF design

I. Introduction

CMOS: inadequate for analog and RF design? Limited active, passive devices Optimized technology for digital design Poor characterization and modeling

Sophisticated set of characteristics speed, noise, linearity, loss, matching, and

dc characteristics Technology characterization methods

II. Motivation and Issues

Tradeoff difference digital CMOS technology vs. analog circuits

speed power dissipation

II. Motivation and Issues

Need for analog characterization Inaccurate modeling, lack of modeling Rapid migration of digital circuits

Difficulties Various systems Difficult to measure Difficult to incorporate in simulations Time and effort Modification for next generation

III. Characterization for analog design

A. DC BehaviorB. AC BehaviorC. LinearityD. MatchingE. Temperature DependentF. Noise

A. DC Behavior

Have measured I-V data points Subthreshold characteristics of MOSFET Output resistance of short-channel MOS tran

sistors

B. AC Behavior

device level and must be measured under bias conditions Nonlinearity of MOS gate-channel capacitance Capacitance of the n-well to the substrate

circuit level Frequently used building blocks as test vehicles (e.g.

ring oscillators) Voltage comparator for intrinsic speed of the

technology

C. Linearity

Passive devices . Coefficients must

be measured Active devices

Minimize the nonlinearity by adequate open-loop gain

Quantify the overall nonlinearity using Fig.10

D. Matching

E. Temperature Dependence

Basic device parameters Output resistance, subthreshold conduction, capac

itance Other quantities

Transconductance, on-resistance, threshold voltage, ac properties

DC and AC temperature dependencies of devices must be measured and incorporated in simulations

IV. Characterization for RF design

A. Device PropertiesB. NoiseC. Circuit Properties

A. Device Properties

Limit active devices, More passive monolithic devices

Inductors - measured data for parameters Varactors Transformers

B. Noise

Thermal noise of submicrometer MOS transistor long-channel approximation Capacitive coupling of the drain noise c

urrent to the gate Modulation of the threshold voltage by t

he body thermal noise 1/f noise of MOSFET’s Values to be measured

are too small to be sensed

C. Circuit Properties

Dependent on Overall transceiver architecture Intended wireless standard

Issues in today’s RF CMOS design Variability of device and circuit parameters

with process and temperature Matching properties Frequency divider Power Amplifiers

Thank you !

Q & A