For today's DDR/IO designs, reliable and predictable chip-to-chip signal transmission depends on the quality of the voltage delivered to the I/O circuit and the magnitude of the signal-to-signal and signal-to-power coupling. Validation of high-speed parallel I/O interfaces requires simulation of an entire I/O bank together with the entire power distribution network for the die, package and the PCB. This presentation discusses Sentinel-SSO™ and how its underlying technologies deliver sign-off accurate I/O-SSO verification with the capacity to handle an entire I/O bank. Learn more on our website: https://bit.ly/1qklvW0

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Sentinel-SSO: Full DDR-Bank
Power and Signal Integrity
Design Automation Conference 2014

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Requirements for I/O DDR SSO Analysis
Modeling
– Package and board
– I/O circuit and layout
– PI + SI feedback
Tool
– Full bank capacity
– Integrated modeling and
simulation environment
– Prototyping and what-if

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Parallel I/O Design and Technology Trends
Noise
 Reduced voltage and supply
noise margin
0
2
4
6
8
10
0
0.5
1
1.5
2
DDR2 DDR3 DDR4
% Noise
Supply
Supply voltages
% noise
Timing
 Reduced timing margins with
higher frequency
3D-IC/Interposers
 Wide-IO with interposer/3DIC
for higher performance and
low power

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Power Integrity Effects on Timing

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Power Integrity Effects on Timing
Low Supply Noise
Similar delay/slew

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Power Integrity Effects on Timing
Moderate Supply Noise
Varying delay/slew

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Power Integrity Effects on Timing
High Supply Noise
Increased Jitter Impact

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Sentinel-SSO: SI + PI for High-Speed DDR I/O
– Complete System Simulation environment
– GUI based easy setup
– High Capacity full bank analysis
– On-chip PDN/SI modeling
– DDR JEDEC sign-off

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Grid Weakness Reports
Chip-Package-System
SSO Analysis
SSO Noise on
Sensitive IP
Chip-Signal-Model
CSM
JEDEC Signoff Reports
Sentinel-SSO
IC Data Channel Database
3D PKG
Extraction
Multi-Simulator
Support
Chip IO
Modeling
Memory IO Model
Chip Grid
Modeling
PI/SI Co-analysis Using Sentinel-SSO

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Modeling Requirements for SSO Analysis
– Accurate on-chip grid model
– I/O models capturing impact of PDN noise
– Accurate Power and Signal channel model
– Accurate receiver models
VRM Terminations
I/O
On-chip
Grid
Power
Channel
Signal
Channel
Chip Channel Receiver

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Power Noise Impact on Signal Integrity
Coupling in PKG/PCB reduced
Modeling of Power Noise
– On-chip PDN
– Package Impedance
– Accurate IO modeling
Eye: with and without Power Noise
With Power Noise
Without Power Noise
Source PG Bump
Veff noise
Strobe jitter DQ Jitter
SNSSO 71mv 43.2ps 99.1ps
Measured 73mv 42.0ps 92ps
Accurate Measurement Correlation

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Sentinel-SSO: I/O Buffer Modeling
– CIOM: Non-linear device I/O buffer macro-model
– Spice-level accuracy with full I/O bank capacity
– Captures impact of P/G noise on signal
– Load independent
– Layout and circuit IP encryption

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Full I/O Bank Capacity
– 32bit and 64bit simulations common
– Possible to simulate over 250 instances
Size Run Time Simulation Time
1 byte (all ciom) 25min 60ns
1 byte (all xtor) 34hrs 39min 60ns
4 bytes (all ciom) 2hrs 60ns
IO Bank

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Accurate On-die Modeling
– Lumped models miss impedance and voltage variation across bank
– Lumped models have less bandwidth
– Reduced grid can model thousands of nodes
Measurement correlated
Cdie comparison
Blue – CSM
Green – meas. biased
Red – meas. unbiased
Lumped impedance
(bottom yellow)
Distributed impedance
per instance
Frequency
Impedance

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Signal/PG Coupling in Channel
– DDR signal routing coupled to custom
PG routing of PLL in package and board
– PLL supply noise at metal1 level on chip
determines circuit behavior
DDR Bank
I/O PG Supply PLL
PLL PG Supply
Coupling in PKG/PCB reduced
Runtime reduced from 64hrs to 24min with CIOM
“System Level PDN Analysis Enhancement Including
I/O Subsystem Noise Modeling” DAC 2013

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Accurately Capture Quiet Line Noise
Noisy
Quiet
VSS has noise at chip
Similar to VDD noise
Signal supplied by
PG voltage of driver
2x Noise
Asymmetric
S-parameter pkg models
cannot model reference-to-reference
voltage differences!
Symmetric
RLCK package models allow for physical
meaning to be assigned for voltage
differences between all terminals

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Sentinel-SSO Modeling Technologies
Technology Impact Benefits
Grid Modeling Accuracy
 Captures on-die PDN noise
 High bump resolution
Chip IO Modeling Capacity
 Efficient behavioral model
 Captures power noise impact
 High capacity simulation
Channel Modeling Accuracy  True signal propagation
DIE
I/Os
Package/Brd

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Simulation & Reporting
– Delay, Slew, Eye automatic measurements
– JEDEC standard reporting
– User configurable reports

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Chip Aware System SI Using CSM
• IP protected model of PHY
• Model captures on-die PI/SI
• Light weight behavioral model
• Enables system level SI analysis
v
time
Ω
freq
v
time
Power Nets
Ground Nets
Signal Nets

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Summary
• GUI based setup and simulation
– Graphical connections and early analysis
– Tcl commands to support batch mode operation
• Accurate and efficient modeling
– CSM, efficient IP neutral model of chip I/O bank
– S-param conversion and SCB optimization
• Reporting
– Find and root cause die grid weaknesses
– Waveforms, eye-diagrams, JEDEC
Sentinel
SSO
JEDEC
Reporting
Prototyping
Channel
Optimization
Model
Generation