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10GBASE-CX4 Link Analysis Outline10GBASE-CX4 Link Analysis Outline10GBASE-CX4 Link Analysis Outline

• Link Model Definition• Cable Specifications v.s. Measurements• Transceiver Specifications v.s. Measurements•• Link SimulationsLink Simulations• Summary / Recommendations

10GBASE-CX4 2 / 82

Frequency (Hz)

Loss

(dB

)

S-parameters to Pulse ResponseS-parameters to Pulse ResponseS-parameters to Pulse Response

Return Loss

Insertion Loss

Frequency (Hz)

Pha

se (r

adia

ns)

Frequency (Hz)

Pha

se (r

adia

ns)

Loss

(dB

)

Frequency (Hz)

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S-parameters to Pulse ResponseS-parameters to Pulse ResponseS-parameters to Pulse Response

MDNext

MDELFext

Frequency (Hz)

Loss

(dB

)

Frequency (Hz)

Pha

se (r

adia

ns)

Frequency (Hz)

Pha

se (r

adia

ns)

Loss

(dB

)

Frequency (Hz)

10GBASE-CX4 4 / 82

Frequency Response for DFTwith Fs=12.5-GHz

Φ S

21 (

radi

ans)

|S21

|

Frequency (MHz)

Impulse Response: IFFT

Inve

rse

Fou

rier

Tra

nsfo

rmTime (ps)

Nor

mal

ized

Am

plitu

de

MA

TLA

B

Amplitude

Phase

Inverse DFT to Obtain Impulse ResponseInverse DFT to Obtain Impulse ResponseInverse DFT to Obtain Impulse Response

10GBASE-CX4 5 / 82

TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

++

MDELFext MDNext, Dj,Rjtx, Rjrx , Rl

Eye = 0mVppMargin = -258mVpp

Eye = 81mVppMargin = 39mVpp

Eye = 400mVppMargin = 400mVpp

D4.0 Link Simulation ResultsD4.0 Link Simulation ResultsD4.0 Link Simulation Results

• Typical Eye Diagrams for Nominal Pre-emphasis = 50%

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Equalization OptimizationEqualization OptimizationEqualization Optimization

2/3 Worst Case Insertion Loss Margin vs Pre-emp vs Rx Eq.Worst Case Insertion Loss

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MDNext SensitivityMDNext SensitivityMDNext Sensitivity

Current Model 1Eye = 178mVpp

Margin = 127mVpp

TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

+

MDNext

Frequency (Hz)

Loss

(dB

)

Model Eye Margin1 178 1272 157 1063 158 1054 157 1055 156 105

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TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

+

MDELFext

MDELFext / MDFext SensitivityMDELFext / MDFext SensitivityMDELFext / MDFext Sensitivity

Model 3Eye = 262mVpp

Margin = 202mVppFrequency (Hz)

Loss

(dB

)

Model Eye Margin1 242 2642 247 1723 262 2024 262 2005 262 194

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Amplitude SensitivitiesAmplitude SensitivitiesAmplitude Sensitivities

MDNext Amplitude vs Margin MDFext Amplitude vs MarginTx Amplitude vs Margin

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Cable Assembly Return Loss SensitivityCable Assembly Return Loss SensitivityCable Assembly Return Loss Sensitivity

TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

+

Rl

Model 5Eye = 262mVpp

Margin = 202mVppFrequency (Hz)

Loss

(dB

)

Model Eye Margin1 171 962 176 1173 175 1154 161 1005 205 243

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Jitter SensitivityJitter SensitivityJitter Sensitivity

TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

+

Dj, Rjtx, Rjrx

UI

Mar

gin

Loss

(mV

ppd)

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IL = Current SpecRL = Model #5MDFext = Model #3MDNext = Current SpecTrf = 130psV(fext) = 1.2VppdV(next) = 1.0VppdV(tx) = 800mVppdDj = 0.085UiRj = 4.2ps rmsRx Pole = 400MHz

Worst Case SimulationWorst Case SimulationWorst Case Simulation

TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

++

MDELFext MDNext, Dj,Rjtx, Rjrx , Rl

Tx Pre-emphasis

Mar

gin

\ Eye

Ope

ning

(mV

ppd)

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TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

++

MDELFext MDNext, Dj,Rjtx, Rjrx , Rl

D4.1 Cable Assembly Model?D4.1 Cable Assembly Model?D4.1 Cable Assembly Model?

• Typical Eye Diagrams for Nominal Pre-emphasis = 36%

Eye = 86mVppMargin = -3mVpp

Eye = 38mVppMargin = -17mVpp

Eye = 400mVppMargin = 400mVpp

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TP6RX Slicer

B1

Rx EqualizerTx Pre-emphasis

TP0 TP2 TP3TP1 TP4 TP5

A

HPCB

B2HPCB

TX Driver

HcaHPK HPK

++

MDELFext MDNext, Dj,Rjtx, Rjrx , Rl

Eye = 0mVppMargin = -258mVpp

Eye = 81mVppMargin = 39mVpp

Eye = 400mVppMargin = 400mVpp

D4.0 Link Simulation ResultsD4.0 Link Simulation ResultsD4.0 Link Simulation Results

• Typical Eye Diagrams for Nominal Pre-emphasis = 50%

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10GBASE-CX4 Link Analysis Outline10GBASE-CX4 Link Analysis Outline10GBASE-CX4 Link Analysis Outline

• Link Model Definition• Cable Specifications v.s. Measurements• Transceiver Specifications v.s. Measurements• Link Simulations•• Summary / RecommendationsSummary / Recommendations

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Cable Assembly Summary /Recommendations

Cable Assembly Summary /Cable Assembly Summary /RecommendationsRecommendations

• MDELFext is to large and doesn’t match measured cableassemblies, change to:– MDELFext >= 15 - 21.85 x log10(Freq/50) for 50MHz < Freq = 17 - 21.85 x log10(Freq/50) for 50MHz < Freq = 30 - 13.33 x log10(Freq/30) for 10MHz < Freq = 15 for 400MHz < Freq = 15 - 34.3 x log10(Freq/1250) for 1250MHz < Freq

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Transmitter Summary / RecommendationsTransmitterTransmitter Summary / Recommendations Summary / Recommendations

• Transmit amplitude range is to large allowing for thecreation of excessive Next, adopt the followingspecification:– Differential peak amplitude lane to lane difference shall be less then

200mVpp.

• Transmit amplitude range is to large allowing for thecreation of excessive Fext, make the following change:– Differential peak amplitude, maximum, section 54.7.3.4, shall be less

than 1200mVpp.

• Adopt the transmit template submitted by Ze’ev Roth andscaled for 36% pre-emphasis

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