xlaui/caui electrical specificationsieee802.org/3/ba/public/may08/ghiasi_01_0508.pdf · ieee...
TRANSCRIPT
IEEE 802.3ba Interim Meeting 1
A. Ghiasi 1/22
XLAUI/CAUI Electrical Specifications
IEEE 802.3baMunich
May 13 2008
Ali GhiasiBroadcom Corporation [email protected]
802.3 HSSGNov 13, 2007
Ryan LatchmanGennum Corporation
802.3 HSSGNov 13, 2007
IEEE 802.3ba Interim Meeting 2
A. Ghiasi 2/22
List of Supporters and Contributors
• John Petrilla – Avago• Petar Pepeljugoski IBM• Tom Palkert – Luxtera• Jim Tavacoli Santur• Frank Chang Vitesse
IEEE 802.3ba Interim Meeting 3
A. Ghiasi 3/22
Overview
• XLAUI/CAUI interface• Application of XLAUI/CAUI• Learning form XFP and SFP+• Optimized electrical interface for XLAUI/CAUI• Channel data for Fr48 and Fr413• Channel simulation
IEEE 802.3ba Interim Meeting 4
A. Ghiasi 4/22
XLAUI/CAUI Interface
• Simple, low power chip to chip or chip to module interface.
– Simplifies ASIC SerDes by not requiring to support TP1/TP4 requirements for all PMD's.
• Retimed interface with relax jitter budget and ASIC friendly.
• Take advantage of preemphasis to increase PCB loss with simple CDR receiver.
• Operate over ~8” FR48 stripline or ~12” FR413 stripline.
• XLAUI/CAUI will be the bolting point for future PMDs based on 25 GBd.
MAC/RS
XLAUI/CAUIExtender Interface
PMD Service Interface
Medium MDI
PCS
FEC
PMA
PMA
PMA
PMD
see ganga_01_0508.pdf for XLAUIand CAUI layer definition
IEEE 802.3ba Interim Meeting 5
A. Ghiasi 5/22
Application Not Using XLAUI/CAUI
• ASIC capable of interfacing with the PMD are not required to use the XLAUI/CAUI retimer, see petrilla_01_0508.pdf.
• Likely scenario are:– A simplified ASIC supporting single PMD type– ASIC SerDes support all PMDs when the technology is mature and there is
little power penalty (i.e. SFP+ now).
ASIC ASIC
TP1 TP4TP2 TP3
PMD/Module
PMD/Module
TP3 TP2TP4 TP1
IEEE 802.3ba Interim Meeting 6
A. Ghiasi 6/22
Application XLAUI/CAUI Extender for Front Ports
• Application with Retimer in the module (QFP/CFP)
• Application with Retimer on the host PCB (QSFP/CSFP)
TP1 TP4TP2 TP3TP0 TP5A B A B
XLAUI/CAUI
XLAUI/CAUI
ASIC
TP2 TP3A B A B
PMD*/ Module
XLAUI/CAUI
XLAUI/CAUI
PMD*/Module
Ret
imer
Ret
imer
ASIC
AB B A
ASICASIC PMD*/Module
PMD*/Module
Ret
imer
TP1 TP0 ABAB TP3 TP2TP4TP5
TP3 TP2
Ret
imer
IEEE 802.3ba Interim Meeting 7
A. Ghiasi 7/22
Application XLAUI/CAUI Extender for Backplane Ports
• Backplane application with XLAUI/CAUI Retimer
• Backplane application without XLAUI/CAUI Retimer
TP1 TP4
>ASICASIC
TP1TP4
><<
TP1 TP4
>A B A B
XLAUI/CAUI
XLAUI/CAUI ASICASIC
PMA/
PMD
TP1 ABAB TP4
><<
PMA/
PMD
IEEE 802.3ba Interim Meeting 8
A. Ghiasi 8/22
XLAUI/CAUI Electrical Interface
• XFI has very stringent SDD return loss 10 dB up to 7.5 GHz up to 7.5 GHz, CEI more relax with 8 dB up to 7.5 GHz.
– Flat return loss up to 7.5 GHz is not physical, too tight at high frequency, but too loose at the low frequency!
– The proposed XLAUI/CAUI specifications is based on SFF8431 with corner frequency pulled back to 2.125 GHz from 7.5 GHz but with improved return loss up to 2.125 GHz.
• XFI/CEI have very stringent common mode return loss 6 dB up to 15 GHz.
– The proposal here is for SCC to follow SDDxx – 3 dB.– SCC for the receiver is not required as it limits the implementation.
• XFI and SFI allocate only 6 dB of channel loss at ½ the baudrate which has either limited the host PCB and/or material
– The proposed channel increases the loss at ½ the Baudrate to 8 dB for more flexible PCB design.
IEEE 802.3ba Interim Meeting 9
A. Ghiasi 9/22
XFI, CEI, SFP+, CAUI Return Losses• Physical limitation of the IC parasitics makes it difficult to meet XFI return
loss, CEI is too loose at low frequency. – This proposal uses 8.5 SFP+ Host return loss s4p available asT11838v0.
• 12 dB up to 2.125 Ghz, 6.5 + 13.33LOG10(f/5.5) from 2.125 Ghz to 11.1 GHz.
0 1.5 3 4.5 6 7.5 9 10.5 12 13.5 15-15-14-13-12-11-10-9-8-7-6-5-4-3-2-1
SDD11/SDD22
XFP
CEI
SFP+
CAUI
KR
Freq (GHz)
Ret
urn
Loss
(dB
)
IEEE 802.3ba Interim Meeting 10
A. Ghiasi 10/22
XFI, CEI, and CAUI/XLAUI RL– XFP/CEI common mode more difficult than SDD and not practical!– SFP+ defines SCC to follow the SDD mask but 3 dB worse:
• 9 dB from 0.1 to 2.125 Ghz, (3.5 + 13.333LOG10(f/5.5)) from 2.125 to 7.1 Ghz, 2 from 7 to 11.1 GHz.
0 1 2 3 4 5 6 7 8 9 10 11 12-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
SCC22
XFP/CEI
CAUI
Freq (GHz)
Ret
urn
Loss
(dB
)
IEEE 802.3ba Interim Meeting 11
A. Ghiasi 11/22
RX/TX Chip Return Loss
• CAUI SDDxx mask overlayed on top of the 8.5Gig SFP+ Host return loss, s4p file is available from T11 website as T11838v0.
SDD Mask=12 if <2.125 GHz else 6.5 + 13.33*LOG10(f/5.5), where f is in GHz
IEEE 802.3ba Interim Meeting 12
A. Ghiasi 12/22
XLAUI/CAUI Channel Loss Budget
• XFI, SFP+, and CEI 11GSR operate only over ~6” of FR48 stripline• The proposed channel loss for XLAUI/CAUI increases the loss to 8
dB at ½ the baudrate to allow up to 8” of FR48 stripline traces with one connector for more flexible host design.
– Use of transmit preemphasis and more relaxed jitter allows increasing the channel loss budget.
Parameters Ch Loss @5.5 Gig Units
Channel Loss SDD21 Including Up to One Connector 81 dB
Penalty for Reflections and Other Penalty 3 dB
Total Loss 11 dB
1. SDD21=0.137 – 1.073*SQRT(f) – 1.08*f, f unit is in Ghz.
IEEE 802.3ba Interim Meeting 13
A. Ghiasi 13/22
XLAUI/CAUI Channel Return Loss Requirement
• Ch=14.5 from 0.01 to 5 GHz and 23.25*8.75*(f/5), where f is in GHz.
0 1 2 3 4 5 6 7 8 9 10 1120
18
16
14
12
10
8
6
4
2
Ch
Frequency (GHz)
SD
D11
/SD
D22
(dB
)
IEEE 802.3ba Interim Meeting 14
A. Ghiasi 14/22
Channel Description
• All channels were measured with SFF8083 connector.• FR413 channels have two 15 mils via stubs.• FR48 channels has one 13 mils via stub plus the SMA stub.
Legend Description
SDD21_Mask Proposed XLAUI/CAUI Channel
SDD_FR13_6in
SDD_FR13_8in
SDD_FR13_12in
SDD_FR8_4in
SDD_FR8_6in
SDD_FR8_8in
FR413 Stripline with 5 mil wide traces 150 mm long
FR413 Stripline with 5 mil wide traces 200 mm long
FR413 Stripline with 5 mil wide traces 250 mm long
FR48 Stripline with 5 mil wide traces 100 mm long
FR48 Stripline with 5 mil wide traces 150 mm long
FR48 Stripline with 5 mil wide traces 200 mm long
IEEE 802.3ba Interim Meeting 15
A. Ghiasi 15/22
XLAUI/CAUI Channel Model• Channel model based on 8” of 5.5 mils FR48 striplines or about 12” of
5.5 mils FR413 striplines
IEEE 802.3ba Interim Meeting 16
A. Ghiasi 16/22
XLAUI/CAUI Transmitter Electrical Specifications (Point A)
• Starting with SFF8431 specification at AParameter Symbol Conditions Min Typ Max Units
Differential Output Voltage, pp Vdiff see 1 mV
Termination Mismatch at 1 MHz 5 %
Output AC Common Mode Voltage (RMS) Vcm 15 mV
Output Rise and Fall time (20% to 80%) tRH, tFH 24 ps
Differential output Sparameters
for
SDD22 0.01 to 2.125 GHz 12 dB
2.12511.1 GHz *2 dB
Common Mode Output Sparameters SCC22 .012.125 GHz 9 dB
2.1257.1 GHz * 3 dB
7.111.1 GHz 2 dB
1. Must meet eye mask parameter Y1 and Y2.
2. SDD22(dB) = 6.5 + 13.33*LOG10(f/5.5), f is given in GHz
3. SCC22(dB)= 3.5 + 13.33*LOG10(f/5.5), f is given in GHz
IEEE 802.3ba Interim Meeting 17
A. Ghiasi 17/22
XLAUI/CAUI Transmit Eye Mask (Point A)Parameter Symbol Conditions Min Typ Max Units
Determinstic Jitter 0.17 UI
Total Jitter TJ 0.32 UI
Eye Mask X1 0.16 UI
Eye Mask X2 0.38 UI
Eye Mask Y1180
mV
Eye Mask Y2 350 mV
Diff
eren
tial A
mpl
itude
(V)p
p
Y2
0
Y1
Y1
Y2
X1 X2 1X2 1X1Normalized Bit Time (UI)
IEEE 802.3ba Interim Meeting 18
A. Ghiasi 18/22
XLAUI/CAUI Receiver Electrical Specifications (Point B)
• Starting with SFF8431 Receiver specification
Parameter Symbol Conditions Min Typ Max Units
Differential Input Voltage , Differential pp Vdiff see 1 110 850 mV
Output AC Common Mode Voltage (RMS) Vcm 20 mV
Output Rise and Fall time (20% to 80%) tRH, tFH 24 ps
Differential output Sparameters SDD11 0.05 to 2.125 GHz 12 dB
2.12511.1 GHz *2 dB
Differential to Common Mdoe Input ConversionSparameters
SCD11 0.0111.1 GHz15
1. Max value is 850 mV for compatablity with TP4 see petrila_01_0508.pdf
2. SDD22(dB) = 6.5 + 13.33*LOG10(f/5.5), f is given in GHz.
IEEE 802.3ba Interim Meeting 19
A. Ghiasi 19/22
XLAUI/CAUI Receive Eye Mask SpecificationsParameter Symbol Conditions Min Value Max Units
nonEQJ Jitter (TJ – ISI) DJ Corner Frequncy>4 MHz 0.42 UI
Total Jitter TJ Corner Frequncy>4 MHz 0.62 UI
Eye Mask X1 0.31 UI
Eye Mask X2 0.5 UI
Eye Mask Y1 55 mV
Eye Mask Y2 425* mV
* same as SFP+
Diff
eren
tial A
mpl
itude
(V)p
p
Y2
0
Y1
Y1
Y2
X1 X2 1X1Normalized Bit Time (UI)
IEEE 802.3ba Interim Meeting 20
A. Ghiasi 20/22
Link Simulation Setup
• Host SerDes package model was cascaded with the channel– SerDes random jitter, SerDes DJ, and connector crosstalk are not included
in the simulation.
SerDesPKG
S4pDefinition
Port 1 Port 3
Port 4Port 2
S4P File Definition for Host and Module Sparameters
Chip PCB
>
>
Channel8” Fr48 +
1 Connector
Scope
IEEE 802.3ba Interim Meeting 21
A. Ghiasi 21/22
Channel Simulation
• Output eye digram for the 8 in Fr48 stripline with and without preemphasis.– Does not include crosstalk, phase noise, etc.
α=0 α=0.2
DJ~28 ps DJ~10 ps
2222A. Ghiasi 22/22IEEE 802.3ba Interim Meeting
Conclusion• Based on the ASIC power dissipation concern of supporting all
PMDs, this proposal use a simple SerDes interface like XFI on the ASIC for “Media Extender”.
– Lowest power dissipation for the ASIC and flexible.– ASIC may choose to support the PMD interface.
• XALUI/CAUI electrical interface leverage XFI and SFI works, but with several key improvements:
– Channel length increased to 8” of FR48 or 12” of Fr413 by levering preemphasis
– Return loss based on SFI which is more ASIC friendly than XFI.
• Assuming the PMD interface will use the same return loss and electrical level, then OEM may decide to use a retimer only if they can't meet the jitter requirement at TP1/TP4.