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Chip and Package-Level Wideband EMI Analysis for Mobile DRAM Devices
Jin-Sung Youn (Samsung Electronics)
Jin-Sung Youn, Jieun Park, Jinwon Kim, Daehee Lee, Sangnam Jeong, Junho Lee, Hyo-Soon Kang, Chan-Seok Hwang, Jong-Bae Lee (Samsung Electronics)
Chip and Package-Level Wideband EMI Analysis for Mobile DRAM Devices
Jin-Sung Youn (Samsung Electronics)
Jin-Sung Youn, Jieun Park, Jinwon Kim, Daehee Lee, Sangnam Jeong, Junho Lee, Hyo-Soon Kang, Chan-Seok Hwang, Jong-Bae Lee (Samsung Electronics)
SPEAKERS Jin-Sung Youn
Senior Engineer, Samsung Electronics [email protected], [email protected]
He received the B.S. degree in Information and Telecommunication Electronics Engineering from Soongsil University, Korea, in 2007. He received He received the M.S. and Ph.D. in Electrical and Electronic Engineering from Yonsei University, Korea, in 2014. His doctoral dissertation concerned the high-speed and power-efficient 850-nm Si optoelectronic integrated receivers for optical interconnect applications. In 2014, he joined the Samsung Electronics, Gyeonggi-do, Korea, where he is currently a Senior Engineer. His current research interests include the area of design methodology that include signal integrity (SI), power integrity (PI), electromagnetic interference (EMI), and electrostatic discharge (ESD).
Agenda
Background
Trends of in Mobile Devices
EMI Source in Mobile Devices
Wideband EMI Analysis Methodology
EMI Simulation Flow
Chip/Package-Level EMI Solution
Correlation with Measurement Results
Conclusion
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2006 2008 2010 2012 2014 2016 2018 2020
Thic
kne
ss [m
m]
Year
예상
Sony
Apple
LG
HTC
Samsung
Trends of Mobile Devices
High performance/integration: multi cores, multi functions, huge data processing, ...
800+components in a mobile device
Higher connectivity: GSM, CDMA, UMTS, LTE, Bluetooth/WiFi, GPS, 5G(28GHz) ...
Thin and slim device
Electromagnetic interference (EMI) becomes a critical issue !
Source: www.samsung.com Source: www.phonearena.com
www.bizwatch.co.kr
Prediction
9.9mm
6.8mm
Camera Chip
Evaluation of EMI Characteristics
EMI Issues
RF sensitivity degradation: cellular bands (2G/3G/LTE), Bluetooth/WiFi, GPS
Malfunctions
- Display/camera performance degradation
- Ghost swipe in touch screen panel (TSP)
Set-Level EMI Component-Level EMI
Camera Module
Sensors (Gyro,Accelerometer)
Memory AP
Modem
NFS Chip PMIC
Source: www.samsung.com
▶ Far-Field ▶ TIS
microSD Card
BT/WiFi
▶ Near Field
Near-field scan (NFS)-based EMI analysis is essential !
Classify EM Noises & Find Root Causes
* TIS: Total Isotropic Sensitivity
If Our Products Failed by EMI ...
Most of EMI evaluation and verification rely on testing ...
Requirement of additional cost and time to fix
Effort (cost & time) can be reduced by adopting EMI simulation in the product design stage.
EMI analysis methodologies are strongly required !
Product Design
Fabrication EMI Test Mass
Production Fail
Pass
Product Re-Design
EMI Simulation
Product Design
Fabrication EMI Test Mass
Production Fail
Pass
Product Re-Design
∙ Signal Swing Level ∙ Slew Rate Control ∙ Operating Frequency Change ∙ Chip/PKG/System Revision …
Improved Process
Existing Process
-65
-55
-45
-35
-25
-15
-5
-65
-55
-45
-35
-25
-15
-5
-65
-55
-45
-35
-25
-15
-5
Why We Need Wideband EMI Solution ?
Data rate of mobile DRAMs continuously increases...
LPDDR2(800Mbps) → LPDDR3(1600Mbps) → LPDDR4(3200Mbps) → …
Radio-frequency interference (RFI) between memory and wireless antennas...
[dBm]
[Hz] 1G 2G 3G 4G 5G 0
LTE/GSM GPS /Glonoss
LTE/GSM BT/WiFi
[dBm]
[Hz] 1G 2G 3G 4G 5G 0
LTE/GSM GPS /Glonoss
LTE/GSM BT/WiFi
[dBm]
[Hz] 1G 2G 3G 4G 5G 0
LTE/GSM GPS /Glonoss
LTE/GSM BT/WiFi
LPDDR2 (800Mbps)
LPDDR3 (1600Mbps)
LPDDR4 (3200Mbps)
EMI Sources in Mobile DRAM Devices
Package-on-Package (PoP)
EMI Sources
On-Chip radiation: direct emission (by on-chip interconnection) from chip surface
Off-Chip radiation: signal conductors and power plane from package
I/O
I/O
DRAM#4 DRAM#3 DRAM#2 DRAM#1
On-Chip EM Radiation
VDD
GND
Signal Signal
DRAM Cell
Off-Chip EM Radiation (Power Plane)
Off-Chip EM Radiation (Signal Path)
TOP Package (Memory)
Bottom Package (AP)
Time
Signal Path
Voltage
Time
Voltage
Power Plane
∙ Crosstalk Noise ∙ Timing delay/skew ∙ Jitter ∙ Impedance mismatch
∙ Simultaneous Switching Noise (SSN) ∙ Plane coupling ∙ PWR/GND Impedance
DQ(Ch1.) DQ(Ch2.)
VDDQ(Ch1.) VDDQ(Ch2.)
EMI Simulation Flow
Source: www.google.com
Various circuit/EM simulation tools are available for EMI simulation.
How to increase accuracy of EMI simulation ...?
EMI Source Extraction
Memory read operation at 1.6 Gbps
Block diagram
Memory I/O buffer
Power distributed network (PDN)
Memory/AP package models
Input stimulus
Verify by package direct probing & logic analyzer
Periodic pattern (832bits)
416bit
120bit
…….32bit
0
toggle
0 0
160bit
0
toggle toggle
40bit
32bit 32bit
*Toggle: 1010... Non-Toggle: 0000...
Input
Stim
ulu
s
EMI Source Extraction - I/O Buffer Model
SPICE model provides better accuracy with long simulation time.
IBIS Model
Static and dynamic curves describing electrical behavior of the I/O
Used for fast extraction of basic parameters
* IBIS: I/O Buffer Information Specification
-0.4
0.0
0.4
0.8
1.2
1.6
14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0
Time [ns]
Voltage [V]
IBIS
SPICESPICE Model IBIS Model
IN OUT IN OUT
PMOS
NMOS
Diodes
Cap
Rising Waveforms
Pullup
Pulldown Falling Waveforms
Power Clamp
GND Clamp
Ccomp
∑
∑
Waveform differences btw SPICE and IBIS Models
SPICE model is needed to achieve wideband EMI solution.
Knee
Overshoot
Ringback
High-frequency components
EMI Source Extraction - Power Distributed Network (PDN)
PDN based on R-network can be used for simple and fast simulation.
RC Network is extracted from layout → Accurate PDN effect can be included in our simulation.
Power Plane
Ground Plane
Power Plane
Ground Plane
R Network .subckt DRAM in out vdd vss nmos out in vss vss pmos out in vdd vdd
cdecap vdd vss 10p .ends
…
SPICE Model
.subckt DRAM in out vdd vss nmos out in vss vss pmos out in vdd vdd
cdecap vdd vss 10p .ends
…
SPICE Model
RC Network
▷ Time Domain → No significant difference!
▷ Frequency Domain → ~13dB difference@2nd harmonic
R Network RC Network
-80
-75
-70
-65
-60
-55
-50
DQ
0D
Q2
DQ
4D
Q6
DQ
8D
Q1
0D
Q1
2D
Q1
4
Ma
gnit
ud
e [
dB
]
-80
-75
-70
-65
-60
-55
-50
DQ
0D
Q2
DQ
4D
Q6
DQ
8D
Q1
0D
Q1
2D
Q1
4
Ma
gnit
ud
e [
dB
]
-80
-75
-70
-65
-60
-55
-50
DQ
0D
Q2
DQ
4D
Q6
DQ
8D
Q1
0D
Q1
2D
Q1
4
Ma
gnit
ud
e [
dB
]
800MHz 1600MHz 2400MHz
R Network RC Network
Chip/Package Modeling
Layer/DIE Stack-up Source Attachment
Solderball Bondwire
Package model setting using SIwave
Full Package Model
DRAM#1
Dielectric
Interposer Model (for Testing)
…
Copper
DRAM#N
Chip Metal
Dielectric Copper
…
Dielectric
JEDEC 4-Point Sig. GND
Frequency-Independent Source (FFT Dataset File)
Simple Model
Near-Field Simulation
Simulation is done using SIwave
Frequency range
700MHz~1GHz (501points)
1500MHz~1800MHz (501points)
2300MHz~2500MHz (501points)
[Simulation Results at 800MHz]
Hx Probe Hy Probe Hz Probe
Extract the maximum value btw Hx and Hy probes at each frequency
Correlation (1): Simulation vs. Measurement
Memory read operation (1600Mbps) for each byte
Near-field scan measurement up to 3rd harmonic (800MHz, 1600MHz, 2400MHz)
Error between measurement and simulation is less than 3dB
Simulation is well matched with measurement !!
Byte1
Sim.
Meas.
800 1600 2400 [MHz]
Sim.
Meas.
[MHz]
Byte3
Sim.
Meas.
800 1600 2400 [MHz]
Byte2
Sim.
Meas.
800 1600 2400 [MHz]
EM Field EM Field
Byte0 (Ch1.)
Byte0 (Ch2.)
Byte0
Sim. Meas.
[dBm]
800 1600 2400
[MHz] 800 1600 2400
Sim. Meas.
[dBm]
[MHz] 800 1600 2400
Sim. Meas.
[dBm]
[MHz] 800 1600 2400
Sim. Meas.
[dBm]
[MHz] 800 1600 2400
-80
-60
-40
-20
0
20
2350 2400 2450 2500
H-F
ield
[A
/m]
Frequency [MHz]
-80
-60
-40
-20
0
20
700 750 800 850 900 950 1000
H-F
ield
[d
Bm
]
Frequency [MHz]
-80
-60
-40
-20
0
20
1500 1550 1600 1650 1700 1750 1800
H-F
ield
[A
/m]
Frequency [MHz]
Correlation (2): Simulation vs. Measurement
Memory read operation (1600Mbps) with all byte simultaneously
Near-field scan (NFS) measurement up to ~2.4GHz
Correlation between measurement and simulation is about 89.4%
All Byte (Byte0-3@Ch1./Ch2.)
EM Field EM Field [dBm]
[MHz] 700 800 900 1000 1500 1600 1700 1800 2350 2500
0
20
-20
-40
-60
2400 2450
Simulation Measurement
Conclusion
Wideband EMI Analysis Methodology for Mobile DRAM Devices
Chip/Package-Level EMI Solution and its Detail Analysis Strategies
I/O and Power Distribution Network Models
Chip/Package Modeling
Correlation with Near-Field Scan Measurement Results
Wideband spectrum (~2.4 GHz) with correlation factor of 89.4 %
