Ansoft Ansoft Designer Designer

with with NexximNexximStatistical

EyeCapabilities

0

P o rt2P o rt1TRL

TRL

TRL

TRL

TRL

TRL

Buffer

P la n a rE M

Load Generic0.25um M odels

P C IEConnectorBYPASS

Pro

gra

mm

ab

leW

-Ele

me

nt

SI W

ave

SS

SS

SS+

Complex system analysisSpecification BER analysisBuffer designIntegration of modeling typesEqualization schemesFrequency & Time domain mapping

Problem Statement

Low BER Necessitates

simulation with LARGE bit count

Low BER Necessitates

simulation with LARGE bit countLARGE bit count

Generic SolutionsMultiple tools from different EDA vendors

Spice 1. Many Spice solutions have difficulty handling frequency to time

domain transformsThree-dimensional EM solutions

2. Most time domain simulation tools require s-parameter outputs (see issue 1)

Statistical analysis3. Most dont support mixed elements from within Spice (i.e. w-

elements, s-parameters, transistor and behavioral buffers)Speed

4. Many EDA vendors only support transient analysisCapacity

5. Many solutions support up to a maximum of around 10 20 ports usually requiring s-parameters (see issue 1)

6. Most only allow s-parameter referencing to 50 ohms. This is a problem for SSO/SSN simulations that need power planes referenced to lower impedances, ~1 ohm, for increased numerical accuracy (see issue 1)

Interoperability of EDA tools!

Ansoft Designer with Nexxim OverviewMultiple Analysis domains

Time and Frequency consistencyHigh speed & capacityTransistor-level accuracy

Native supportHSpice netlists & design kits Spectre/SpectreRF netlists & design kits IBIS v4.0 & Verilog-A

Superior S-Parameter HandlingState-Space and ConvolutionBenchmarked 660 ports!Mixed port impedances

Flexibility in design flow and integrationAnsoft DesignerCo-simulation with Ansoft EMCadence ADEMultiple output/viewing formats

Applications in Signal Integrity, Mixed-Signal and Analog Design

Applications in Signal Integrity, Mixed-Signal and Analog Design

NexximNexxim

Ansoft Designer with Ansoft Designer with NexximNexximIntegrated Circuit SimulationIntegrated Circuit Simulation

3rd Party ToolsSimuLink

Matlab

EM ToolsHFSS

SIWaveQ3D

2D ExtrPlanarEM

Time Freq

System

AnalogDigital

MixedSignal

Hspice Spectre VerilogA

AnsoftAnsoftDesignerDesigner

CadenceCadenceADEADE

Latest Developments

Nexxim circuit simulation enhancementsPassivity and State-space AlgorithmsSpeed and accuracyDesign flow

VerifEyeTM

QuickEyeTM

Post-processing

Circuit simulation challenges:Reliable Bit Error Rate (BER)Prediction at FAST simulation speeds

High Speed Channel Analysis

0

P ort2P ort1TRL

TRL

TRL

TRL

TRL

TRL

Buffer

P la n a rE M

Load Generic0.25um Models

P C IEConnectorBYPASS

Prog

ram

ma

ble

W-E

lem

en

t

SI W

ave

SS

SS

SS+

Statistical Eye OverviewTransient Eye requires 1/BER time

1x1015 bits not uncommon Long transient simulations

Approximations are neededStatistics

VerifEyeTM"Rise time" calculation for BER

QuickEyeTMStep" and ISI characteristic calculate BER

Algorithm:Run transient

Generates step responseDetect the delayImpose the step response

On UI grid Calculate probability of error (BER)

For a single cell in the gridBased on statistical assumptions

Generate Eye contourAssumes LTI

VerifEyeVerifEyeTMTM

Statistical Eye Analysis(lower accuracy, highest speed)

Statistical Eye Analysis(lower accuracy, highest speed)

VerifEyeVerifEyeTMTMAdvantages:

SPEED!Mixed model channel

W-elementsS-parametersSpice

Visualizes worst eyeTX jitterTX DCD

QuickEyeQuickEyeTMTM

Algorithm:Run transient

Generates step responseConvolve

Input bit-stream with step responseAllows for very long input bit patternsProvides fast time and eye plotsAssumes LTI system

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00Time [ns]

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

V(P

ort1

) [m

V]

Ansoft Corporation Nexxim1XY Plot 1Curve Info

V(Port1)Transient

Bridge between Statistical Eye & transient (medium accuracy, medium speed)

Bridge between Statistical Eye & transient (medium accuracy, medium speed)

QuickEyeQuickEyeTMTM

Advantages:SPEED!View full transient outputDetect Worst Case PacketVisualize eye mask violations

Determine Jitter through Histogram of threshold crossings

View Eye Diagrams at Various Points

All components "Active"All components "Active"

North Bridge

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

aeye

prob

e846

[V]

2.00 2.00 2.00 2.00 2.00Time [us]

-1.50

-0.50

0.50

1.50

aeye

prob

e846

[V]

Ansoft Corporation SI ChaneXY Plot 1

Curve Infoaeyeprobe846

QuickEyeAnalysis

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e849

[V]

1.9990 1.9995 2.0000 2.0005 2.0010Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e849

[V]

Ansoft Corporation SI ChaneXY Plot 1

Curve Infoaeyeprobe849

QuickEyeAnalysis

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e856

[V]

2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e856

[V]

Ansoft Corporation SI ChaneXY Plot 1Curve Info

aeyeprobe856QuickEyeAnalysis : QuickEyeAnalysis

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e859

[V]

2.00 2.00 2.00 2.00 2.00 2.00 2.00Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e859

[V]

Ansoft Corporation SI ChaneXY Plot 1Curve Infoaeyeprobe859

QuickEyeAnalysis

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e862

[V]

2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e862

[V]

Ansoft Corporation SI ChaneXY Plot 1Curve Infoaeyeprobe862

QuickEyeAnalysis

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e865

[V]

2.00 2.00 2.00 2.00 2.00Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e865

[V]

Ansoft Corporation SI ChaneXY Plot 1Curve Infoaeyeprobe865

QuickEyeAnalysis

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e859

[V]

2.00 2.00 2.00 2.00 2.00Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e859

[V]

Ansoft Corporation SI ChaneXY Plot 1Curve Infoaeyeprobe859

QuickEyeAnalysis

0.01 0.01 0.01 0.02 0.03 0.03 0.04 0.04 0.04Time [us]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e859

[V]

Ansoft Corporation SI ChaneXY Plot 2Curve Infoaeyeprobe859

QuickEyeAnalysis

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e859

[V]

2.00 2.00 2.00 2.00 2.00Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e859

[V]

Ansoft Corporation SI ChaneXY Plot 1Curve Infoaeyeprobe859

QuickEyeAnalysis

Effect Of Connector

All other components "Active"All other components "Active"

Connector In CircuitConnector In Circuit

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [ps]

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

aeye

prob

e859

[V]

1.998 1.999 2.000 2.001 2.002Time [us]

-2.00

-1.00

0.00

1.00

2.00

aeye

prob

e859

[V]

Ansoft Corporation SI ChaneXY Plot 1Curve Infoaeyeprobe859

QuickEyeAnalysis

Connector "Bypassed"Connector "Bypassed"

High Speed Channel Example

Simulation time ComparisonTransientQuickEyeVerifEye

Simulation time ComparisonTransi