菅谷英彦、アーサー シャルデンブランド、佐藤伸久 Cadence Design Systems, Japan 11/19/2013

ミキサー回路のシミュレーション検証手法の考察

電子情報通信学会 アナログRF研究会 第34回 アナログRF研究会

IEEE Solid-State Circuits Society Japan Chapter Thirty Fourth Analog and RF Seminar

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• Review of Mixers and Figures of Merit • Simulation Technologies • Mixer Simulation, the Basics • Mixer Simulation, Advanced Analysis • Summary

Agenda

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Review of Mixers Overview and Figures of Merit

Overview of Mixer • Why do we need Mixers?

− Mixers move a signal from one frequency to another frequency

− From baseband to RF or from RF to baseband

• What does a Mixers do? − The output of a Mixer is a product of

it’s inputs −

• How do we use Mixers? − Frequency Translation − Phase Detection − Phase Shifting

What do we need to know • Performance

− Conversion Gain

• Noise − Noise Figure

• Linearity − Intercept Point − Compression Point

• Non-Ideal Effects − Output LO Feedthrough − Input LO Feedthrough − RF Feedthrough − Image Rejection

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Tools for Mixer Analysis Simulation Technologies

Analyses Time Invariant

Periodic Time

Sampled Periodic

Time

Quasi-Periodic

Time

Measurement, Outputs

Large Signal

DC PSS

QPSS Large-Signal Op Point

Small Signal AC PAC PAC QPAC

Small-Signal Response gain, rejection, …

XF PXF PXF QPXF

Small-Signal Transfer Function

NOISE PNOISE PNOISE QPNOISE Small-Signal Noise

SP PSP QPSP Small-Signal, S-Parameter

STB PSTB Small-Signal Stability Loop Gain, gm, Φm

Rapid IPn Rapid IPn Distortion Analysis, IIP3, IIP2

Transient (Large Signal)

TRAN Large Signal, Transient Response and Noise

Envelope Following

ENVLP Modulated-Carrier Transient Response

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So … Which Engine Should I Use? Harmonic Balance and Shooting Newton are Complementary

• Shooting Newton works well for − Circuits with strongly nonlinear

transient waveforms − Ring oscillators − Frequency dividers

− Input signals have sharp time domain waveform transitions − Switched Cap Filters − DC-to-DC Converters

− Single Tone Circuit

• Harmonic Balance works well for − High dynamic range, weakly-

nonlinear systems − RF front-ends (LNA, Mixer) − IQ modulators − LC and crystal oscillators

− Circuits with distributed components − Transmission lines, S-parameter

models − Multiple Tone Circuits

Harmonic Balance Fast simulation of RF transceivers

Shooting Newton Analysis of strongly nonlinear circuits

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PSS (Periodic Steady-State) Harmonic Balance Algorithm

Initial estimate: Spectral Voltage

Calculate currents

IR IC IL ID ITotal

Converter time freq

Calculate currents

IR IC IL ID ITotal

Converter time freq

Iterate if the current error is greater than the error bound

Ierror

Iterate until Ierror < error bound

Final -1 iteration: Spectral Voltage

Ierror less than the error bound

Ierror

Final Iteration: Spectral Voltage

Vfinal

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Periodic Small Signal Analysis Signal from input baseband to output baseband

Signal from input (baseband+one sideband) to output baseband

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Periodic Small Signal Analysis Rapid IP3

f1 f2 f1 f2

Input

2*f1-f2 2*f2-f1

Output

Simulation Methods IPn measurement

• Sweep PSS • Sweep PSS PAC • PSS PAC Rapid IP3 • DC AC Rapid IP3

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Periodic Small Signal Analysis Rapid IP3

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IP3 Measurement Swept PSS PAC IPn Plot

(1). Swept PSS (2). PAC

(3). IPn plot

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Rapid IP3 Measurement PSS (DC) PAC (AC) Rapid IP3 IPn Plot

(2). PAC + Rapid IP3 Option

(1). PSS

(3). Rapid IP3 plot

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Mixer Testbench Mixer Simulation, the Basic

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Mixer Characterization

Swept HB analysis Rapid IP3 analysis

Noise analysis

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Mixer Verification Reducing Verification Misses

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Variation Aware Mixer Verification

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Mixer Verification Integrating Mixers into Up/Down Converters

Divider ÷2

IQ Mod

VCO

RF BB

Down Converter Testbench with VCO and Divider

IQ Mod RF BB

Down Converter Testbench with noise model

) )

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• In addition to characterizing mixer performance for ideal inputs, sine waves, we need to test performance with modulated inputs – Modulated signals have different average to peak values and often

stress a device more than ideal inputs

Mixer Verification Integrating Mixers into Up/Down Converters

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Challenges From RFIC to Wireless IC

Technologies For RF / Wireless IC “In-Design” methodology • Examples: testbench with estimated parasitics,

Create Worst Case Statistical Corner • Parasitic Aware Design, EAD, supports analog

design

RF “Sign-Off” • EMIR analysis only supports transient analysis • Aging Reliability

Metric Driven Verification • Wireless SoC design requires new methodology to deal with the complexity of the verification task

Product Design • As the level of integration increases, IC, package, and board are becoming more integrated

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• Mixer Block Design – Periodic Steady State Analysis – Rapid IPn – Variation Aware Simulation

• RFIC – Integrating Mixers into Converters

• Wireless SoC Design – Metric Driven Verification – Sign-Off : EM/IR

Summary

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