Large-Signal Network Analyzer Measurementsbenefit

Transistor Modeling

Ahmed Alabadelah, Telemic - ESATMarc Vanden Bossche, NMDG Engineering

Copyright 2003 NMDG Engineering bvba

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Overview• What is a Large-Signal Network Analyzer (LSNA) measurement?• The LSNA advantages in device modeling• LSNA Measurements in ICCAP• Acknowledgement• Conclusion

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What is a LSNA Measurement?

TransistorRFICSystem

RealisticStimulus

RealisticStimulus

Measurement System

1v

1i2v

2i1a

1b

2a

2b

• Physical Quantity– Travelling Waves (A, B)

– Voltage/Current (V, I)

• At all device ports

• Representation Domain– Frequency (f)

– Time (t)

– Freq - time (envelope)

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What is a LSNA Measurement?• Complete and accurate characterization of a HF component

– Complete• the information of the measurement describes completely the state of the device under test• the interaction of the measurement system with the component is taken into account

– Accurate• the measurements are traceable to standards (calibration kit, power and phase standard)

• Under a large stimulus– There is a signal present that potentially results in nonlinear behavior of the

component• Under realistic stimulus

– The stimulus can be chosen close to the signals used in reality• Limitation

– The stimulus needs to be periodic

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The LSNA advantages in device modeling • Measure all characteristics of your DUT making a single connection,

using one measurement setup (the LSNA)– DC (static I/V characteristic),– Small-signal (Scattering parameters), and– Large-signal behaviour (dynamic I/V characteristic)

• Qualify the model accuracy of your device under realistic operation conditions as used in designs– power amplification under dynamic conditions– tuning conditions– high-speed switching

• Identify modeling problems at a single glance– LSNA measurements, e.g., immediately reveal weaknesses in capacitance and

charge models

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LSNA measurements in ICCAP

[Courtesy of Agilent Technologies]

Measurement of component behaviorunder different conditions

• power• frequency• bias• impedance• continuous wave• modulation

sweep of Power Vgs Vds Freq

Coupling of measured characteristics in ICCAP

Model Qualification in ICCAP

Quiescent bias Quiescent bias

Dynamic Loadline “Dynamic gm”Before After

Model Tuning in ICCAP

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Acknowledgement• Dominique Schreurs (K.U.Leuven)• Wladek Grabinski (Motorola Geneva)• Ewout Vandamme (ex - colleague Agilent Technologies)• Agilent Technologies

• Ahmed Alabadelah, who volunteered to present this presentation

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Conclusion• Unique tool for complete large-signal model accuracy assessment under realistic

RF or microwave signals• Reduce number of design cycles and reduce manufacturing costs by anticipating

realistic behavior at the transistor level• Optimize model parameters to LSNA measurements for better simulation

predictions• Benchmark various device models, e.g.,

– BSIM versus MM11 versus EKV versus …– VBIC versus MEXTRAM versus HICUM versus ...

• Build confidence in your model

• NMDG Engineering provides a LSNA measurement service• More information / questions : Marc.Vanden_Bossche@nmdg.be

GSM +32 4 78 288 019