CMOS Technology Characterization for Analog and RF Design Author : Behzad Razavi Presenter : Kyungjin Yoo

Index  Introduction  Motivation and Issues  Characterization for analog design  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  DC Behavior  AC Behavior  Linearity  Matching  Temperature Dependent  Noise

A.DC Behavior Have measured I-V data points Subthreshold characteristics of MOSFET Output resistance of short-channel MOS transistors

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, capacitance 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  Device Properties  Noise  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 current to the gate  Modulation of the threshold voltage by the 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