HighSpeed IO Modules

1
High-Speed IO Modules

• Rizwan Bashirullah
• University of Florida

2
Motivation
IO Bandwidth tracks gate count
Rents rule E.F. Rent, 1960
IC Integration doubles every 18-24 months
INTEGRATED FUNCTION
Moores Law G. Moore, 1965
ITRS Projections Long term Trends
Chip-to-board speed 88GHz by 2020
3
IO Power Budget
Total I/O
3100 Power/Ground (2/3) 2067 Signal I/O
(1/3) 1033
High-Performance I/Os
TX/RX Channels
Num. I/Os
Data rate/channel (Gb/s)
ITRS
of Total I/O
100 88 50 25
10 310 78 7800 6864 3900 1950 15 465 116 11600 1
0208 5800 2900 20 620 155 15500 13640 7750 3875 2
5 775 194 19400 17072 9700 4850 50 1550 388 3880
0 34144 19400 9700
Total I/O Bandwidth
Differential TX/RX I/Os
Power/Data Rate (mW/Gb/s)
100Gb 88Gb 50Gb 25Gb 2.6 2.9 5.1 10.2
Total Chip Power 198 W Total HP I/O Power
99 W
255
mW/Channel
Requirements 1.0mW/Gb TX Channel
1.5mW/Gb RX Channel
4
Channel and Signal Compression
Channel Response
TX Equalizer
RX Equalizer
Data IN
Data OUT
Desired Response
-6dB _at_ 0.25 Rate Frequency
6dB
Desired roll-off
dB
20dB
Equalization
26dB _at_ 25GHz
Channel Response
25GHz

• TX and RX equalization
• Signal bandwidth compression

Frequency (GHz)
Channel lt1dB/GHz roll-off
5
Todays Backplane channel

• High-speed, differential, point-to-point links
• Connect chips on line-cards via the backplane
  channel
• Many components on the signal path

3-5dB/GHz roll-off
SDD21 (dB)
Backplane
Frequency (GHz)
6
Signal Path
Complex Signal Path

• Dispersion (skin-effect, dielectric loss)
• Reflections (impedance mismatches connectors,
  via stubs, device parasitics, package)
• Crosstalk (Near and Far end)
• Via Stub Effects
• Variability

7
Interconnect Channel Characterization

The electronic plumbing approach to interconnect
characterization
Analyzer
Pattern Generator
Equalizer
Passive FIR and Rx
8
Research Test Vehicle (RTV) IC modules
On-chip PRBS
Serializer
IC modules
PLL
Deserializer
CDR
9
25Gb/s TX Core
6.25GHz ILD
12.5GHz OSC
6.25GHz 231-1 PRBS
TX Equalizer
Data Retimer
Backplane
RX Equalizer
10
TX Distributed Equalizer
VDD
50 W
OUT
VDD
F2
F3
M1
F1
50 W
IN
output
Vo-
Vo
S
S
Filter sign
S-
Vi
Vi-
Input stage
I
Filter coefficient
11
Examples
28dB
12
Examples Channel Equalization
Channel Response
OUT
Gatech
Intel
Tyco
IN
TX Equalizer
RX Equalizer
Frequency (GHz)
Gatech
Gatech
Intel
Intel
Gain boost at 6.25GHz
Tyco
Gatech 5dB
Tyco
Intel 9dB
Tyco 18dB
Frequency (GHz)
Frequency (GHz)
13
Eye Diagrams
Gatech
Intel
Gatech
Intel
(dB)
Tyco
Tyco
Frequency (GHz)
14
High Frequency I/O Cores
Integrated I/Os Electrical, Optical, and Thermal
I/O Cores 10-100Gb/s
Terabit Modules
15
Summary

• High-speed IO modules to study Electrical
  Signaling and implications on Power and Thermal
  delivery
• Technology Challenges
• Interfaces
• Chip/package/line card
• Line card/backplane/Line cards
• Electrical Channels
• Higher performance than FR-4
• Crosstalk Issues
• Power delivery
• Integrated power supplies
• Thermal management