working towards an erl baseline - ieee-sa - working group
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Working Towards an ERL Baseline
Richard Mellitz
Samtec
May 2019
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force, Salt Lake City, Utah
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 1
Table of Contents
2IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force
ERL bx parameter determination from package parameters
ERL rx parameter determination
Change ERL computation?
ERL parameter base on IEEE802.3cd and new .3ck contributions• ERL parameters KR
• ERL parameters CR
• ERL parameters AUI C2M
• ERL parameters AUI C2C
Actions
The bx Parameter for ERL is Derived from Package Loss and Reference Channel Loss
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 3
12 mm package
32 mm package
32 mm package
28 dB32 mm
package
The ERL bx parameter is computed from difference in package delay, package loss, and maximum channel loss with packages.
Fitted Loss* Difference Between 12 mm and 30 mm Package is 2.29 dB
4IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force
12 mm pkg
32 mm pkg
*Cd included
Time Delay Difference Estimate Between 12 mm and 32 mm Package is 121.8 ps
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 5
Tpd = 1.2180e-10
Total Ref Loss for a 28 dB Channel (@ 26.36 GHz)
6IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force
32 mm fitted package loss = 4.781 dB
2 x package loss + 28 dB = 38.56 dB
For bx computation, Ilref = 38.562 dB
Determine bx
7IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force
Tpd is the timing difference between pulse responses• Tpd = 1.2180e-10 for .3ck
DIL is the loss difference a the Nyquist frequency • DIL =2.125 dB for .3ck
Define ILref as a required insertion loss • ILref = 38.562 dB for .3ck
Define the loss weight, bx, as:
• 𝛽𝑥 =10
− 𝐼𝐿𝑟𝑒𝑓−Δ𝐼𝐿
20 − 10
− 𝐼𝐿𝑟𝑒𝑓20
𝑇𝑃𝛿 10
− 𝐼𝐿𝑟𝑒𝑓20
• bx= 2.2756 GHz
Recap of rx for ERL Computation
8IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force
The parameter, rx, uses the ERL of the • at the test point where ERL is computed
• other side
𝜌𝑥 = 10−𝐸𝑅𝐿
20
This caps the re-re-reflection at the test point from the DFE range
“mellitz_3ck_adhoc_01_032719” Proposed a Change to ERL Computation
9IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force
The idea was to make it easier to explain.
However. since there is little difference in the ERL results the recommendation is not to change at this point in time
ERL Parameters for KR
KR Tx and Rx device
rx= 0.32
bx = 2.2756 GHz
Tr = 10 ps
N = 200
Nbx=Nb
ERLmin = 12 dB • Includes the impact for a worst
case fixture
KR channel
rx= 0.25
bx = 2.2756 GHz
Tr = 10 ps
N = 3000
Nbx=Nb
ERLmin = 10 dB
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 10
ERL Parameters for CR
CR host
rx= 0.32
bx = 2.2756 GHz
Tr = 10 ps
N = 600
Nbx=Nb
ERLmin= 10 dB
Cable assembly
rx= 0.32
bx = 2.2756 GHz
Tr = 10 ps
N = 2000
Nbx=Nb
ERLmin= 10 dB
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 11
“mellitz_3ck_adhoc_01a_042419” Suggests Host to Module Output ERL Limits Based on Channel Acceptance and VEO
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 12
Channel count
ERLmin < 40*log10(Vf/Pmax)-11VEO > 10 mV
Channel count
ERLmin > 40*log10(Vf/Pmax)-11VEO < 10 mV
ERLmin > 40*log10(Vf/Pmax)-11VEO > 10 mV
ERLmin < 40*log10(Vf/Pmax)-11VEO < 10 mV
ERL Parameters for AUI C2MAUI Host Output
rx= 0.25
bx = 2.2756 GHz
Tr = 10 ps
N = 800
Nbx = 4
ERLmin = 40*log10(Vf/Pmax)-11• For fitting with Np=200
AUI module
rx= 0.32
bx = 2.2756 GHz
Tr = 10 ps
N = 200
Nbx= 4
ERLmin = 12 dB• Should the fixture
delay be on the module side if the connector?
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 13
rx= 0.25
bx = 2.2756 GHz
Tr = 10 ps
N = 800
Nbx = 4
ERLmin = 10 dB
AUI Host Input
ERL Parameters for AUI C2C
AUI C2M Tx/Rx Device
rx= 0.32
bx = 2.2756 GHz
Tr = 10 ps
N = 200
Nbx=Nb
ERLmin = 12 dB • Includes the impact for a
worst case fixture
AUI C2M Channel
rx= 0.25
bx = 2.2756 GHz
Tr = 10 ps
N = 2000
Nbx=Nb
ERLmin = 12 dB
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force 14
Action
15IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force
Uses this document as a baseline for ERL
IEEE802.3ck participants to verify these make sense for their affiliates• Most any COM version 2.52 and higher may be used to compute ERL.
• For C2M hosts, use COM versions later than 2.60• The package is included in the ERL computation.
Thank You!
IEEE 802.3 100 Gb/s, 200 Gb/s, and 400 Gb/s Electrical Interfaces Task Force