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©2009 Integrated Device Technology, Inc.
A Silicon Die as a Frequency Source
IEEE International Frequency Control Symposium Noise & Measurement Techniques Lecture Session A3L-B Newport Beach, CA June 2, 2010
Michael S. McCorquodale, Ph.D. General Manager Silicon Frequency Control Integrated Device Technology 111 W. Evelyn Ave. Suite 210 Sunnyvale, CA 94086 (408) 329-5021 [email protected]
1
PAGE 2 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Overview
Mobius Microsystems and IDT Comments on quartz replacement A silicon die as a frequency source Applications Conclusions
Quartz Replacement Silicon Die Freq. Source Applications Conclusions Mobius and IDT
PAGE 3 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
MOBIUS MICROSYSTEMS AND IDT
Mobius and IDT Quartz Replacement Silicon Die Freq. Source Applications Conclusions
PAGE 4 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Mobius Microsystems
Mobius was founded in 2004 out of the U. of Michigan by M. McCorquodale and R. Brown
Core technology is an all-silicon (CMOS) frequency reference that meets the performance requirements of several applications served by XTALs and XOs
Initial product model was IP and initial IP product has shipped over 10Mu
Mobius transitioned to a component product model in 2006
Initial components were launched in 2008 with modest success
Mobius and IDT Quartz Replacement Silicon Die Freq. Source Applications Conclusions
PAGE 5 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Mobius Microsystems and IDT
Mobius revised its products and embodiments in stealth mode
New components perform significantly better (e.g. total operating power is ~2mA, down from 12mA)
IDT acquired Mobius on Jan. 14, 2010
Silicon Frequency Control (SFC) is a new business unit at IDT focused on quartz replacement with silicon devices
The SFC/IDT silicon die component was announced on Apr. 29, 2010
This talk is about this new silicon frequency reference Mobius and IDT Quartz Replacement Silicon Die Freq. Source Applications Conclusions
PAGE 6 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
COMMENTS ON QUARTZ REPLACEMENT
Quartz Replacement Mobius and IDT Silicon Die Freq. Source Applications Conclusions
PAGE 7 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Quartz Components
Quartz Replacement Mobius and IDT Silicon Die Freq. Source Applications Conclusions
Simple, 2, or 4-pin
Crystal Resonator Broad-based SMD < 40MHz <20c
Crystal Oscillator Broad-based SMD 1–150MHz ~45c to >$2.00
Crystal + PLL IC Broad-based SMD 1MHz–>1GHz > 50c >$2.00 (total)
2-pin Passive XTAL Resonator
Broad-based DIP <40MHz <10c
PAGE 8 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
MEMS-Based Silicon Frequency Sources
Quartz Replacement Mobius and IDT Silicon Die Freq. Source Applications Conclusions
High-Q MHz MEMS resonator Assembled device
Sealed resonator
2-die stack: Resonator + CMOS
High-Q MHz MEMS resonator Assembled device
2-die stack: Sealed
resonator
3-die stack: Resonator + CMOS
PAGE 9 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
CMOS-Based Silicon Frequency Sources
Quartz Replacement Mobius and IDT Silicon Die Freq. Source Applications Conclusions
Single-chip, self-referenced CMOS frequency source (0.13µm)
Single-chip, self-referenced CMOS frequency source (0.13µm)
PAGE 10 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
FBAR-Referenced Frequency Sources
Quartz Replacement Mobius and IDT Silicon Die Freq. Source Applications Conclusions
1.5GHz FBAR frequency source
Shailesh Rai, et al., “A Digitally Compensated 1.5 GHz CMOS/FBAR Frequency Reference” IEEE Trans. on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 57, no. 3, March 2010
PAGE 11 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
A Comparison to Quartz
Quartz Replacement Mobius and IDT Silicon Die Freq. Source Applications Conclusions
MEMS
IDT/Mobius
XO
All packages are DFN 5mmx3.2mm
What is the difference between these devices?
It has been shown that the performance of both MEMS and CMOS oscillators is inferior to quartz
Why choose one device over the other?
Why choose anything but quartz?
PAGE 12 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
What we have seen in the market
What is the value proposition of these new devices? − Performance is inferior to quartz
− These new devices are often lumped together with passives at very low ASP
Proposed value includes: size, lead-time and inventory − In the end these are all cost – that is the only value
proposition
− In the market we see that performance is a threshold and cost is the driver
− The real question: does it meet spec. and is it cheaper?
Quartz Replacement Mobius and IDT Silicon Die Freq. Source Applications Conclusions
PAGE 13 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
A SILICON DIE AS A FREQUENCY SOURCE
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
PAGE 14 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
All-Silicon Frequency Sources
Free-run a CMOS RF LC oscillator at >GHz
Design high-resolution process trimming
Design open-loop temperature compensation
Actively regulate the power supply
Frequency divide by a large factor
Develop a low jitter and stable reference spanning fundamental to overtone XTAL frequencies
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
PAGE 15 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
All-Silicon Frequency Sources
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
Due to the parasitic RL & RC present in a integrated implementation:
RL(T) & RC(T) cause a temperature-induced frequency drift:
Temperature drift is negative, concave down and dominated by RL
RL
L C
RC
PAGE 16 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
All-Silicon Frequency Sources
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
A myriad of 1st, 2nd and 3rd order variables affect error
PAGE 17 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Simplified Reference Oscillator (1st Gen.)
TR[12:0]
Cf [12:0]
TR[12:0]
Cf [12:0]
TC[5:0] TC[5:0]
vctrl(T) VDD
Cv [5:0]
TC[5:0]
vctrl(T) VDD
Cv [5:0]
TC[5:0]
VDD
vbias
VDD
Fixed thin film caps trim nominal
frequency Cv (vctrl(T )) compensates LCO over T
High-swing pMOS cascode bias
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
PAGE 18 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Simplified Reference Oscillator (2nd Gen.)
TR[X:0]
Cf [X:0]
TR[X:0]
Cf [X:0]
VDD VDD
TC in coil is corrected by a
lossy capacitance
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
TC[Y:0]
Cf [Y:0]
TC[Y:0]
Cf [Y:0]
RC[Y:0] RC[Y:0]
Primary source of TC
If a lossy capacitance, RC , can be introduced to cancel RL , the TC will be flat
Enables very low power (~2mA)
€
ω1(T) =ωoCRL (T)
2 − LCRC (T)
2 − L
€
ω1(T) =ωoCR(T)2 − LCR(T)2 − L
=ωo
PAGE 19 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Fringing Fields
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
Package molding compound fills voids between interconnect
Last metal in conformal
process
Epoxy molding compound
The fringing E-field off of the device acts as a parasitic capacitor
The molding compound shifts the frequency due to the fringing E-field (new εr); it also has a TC
The B-field also fringes out of die and can be modulated by eddy currents induced in any metal over or under the device
PAGE 20 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Si=200µm
Faraday Shield
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
Fringing B-field from coil Bond pad
Parasitic capacitance from fringing
E-field
Backside metallization
Topside metallization with dielectric
stand-off
Very thin Si die thickness can be
supported
PAGE 21 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Faraday Shield
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
The process sequence is critical to avoid wafer warping Die are trimmed with a parallel wafer-scale test platform The tested/trimmed silicon die can be packaged in any manner
PAGE 22 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Performance
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
TC is below ±100ppm in production test over 0-70C
Curvature arises from nonlinearity in the TC
The distribution arises from the process variation and the trimming algorithm
PAGE 23 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Performance
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
TC is only one component of total frequency stability
Additional tests include bias sensitivity, wander, HTOL, HAST, 3x solder reflow, and thermal hysteresis
Each line item captures an offset and standard deviation
The final error (±300ppm) is determined from by totaling statistics for these line items
PAGE 24 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Performance
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
Integrated jitter is close to meeting optical
carrier requirements
12kHz to 5M
PAGE 25 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
APPLICATIONS
Applications Quartz Replacement Silicon Die Freq. Source Mobius and IDT Conclusions
PAGE 26 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Applications and Market Sizes
USB: USB flash drive and card reader (UFD/UFCR), etc. Serial ATA (S-ATA): HDD, SSD PCIe: Storage SIM card
Applications Quartz Replacement Silicon Die Freq. Source Mobius and IDT Conclusions
PAGE 27 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Quartz Components
Simple, 2, or 4-pin
Crystal Resonator Broad-based SMD < 40MHz <20c
Crystal Oscillator Broad-based SMD 1–150MHz ~45c to >$2.00
Crystal + PLL IC Broad-based SMD 1MHz–>1GHz > 50c >$2.00 (total)
2-pin Passive XTAL Resonator
Broad-based DIP <40MHz <10c
Applications Quartz Replacement Silicon Die Freq. Source Mobius and IDT Conclusions
PAGE 28 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
A Silicon Die Frequency Source in an MCP
Silicon Die Freq. Source Quartz Replacement Mobius and IDT Applications Conclusions
Assembled MCP
Silicon die frequency
source
Application processor
Dissolved package
The die freq. source assembled in a multi-chip package (MCP) Here the die “looks” like IP to the end user
PAGE 29 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
CoB in USB Drive in Package (UDP)
Applications Quartz Replacement Silicon Die Freq. Source Mobius and IDT Conclusions
USB controller
Silicon die frequency
source Memory
PAGE 30 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
CoB in USB Drive in Package (UDP)
Applications Quartz Replacement Silicon Die Freq. Source Mobius and IDT Conclusions
The die freq. source assembled with a chip-on-board (CoB) process Note that the Faraday shield was dissolved with the package
PAGE 31 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
USB Link Performance
Applications Quartz Replacement Silicon Die Freq. Source Mobius and IDT Conclusions
CMOS
XO
Referenced to CMOS oscillator
Referenced to XO
PAGE 32 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
CONCLUSIONS
Conclusions Quartz Replacement Silicon Die Freq. Source Applications Mobius and IDT
PAGE 33 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
Conclusions
A new silicon die frequency source was introduced where the production qualified performance is ±300ppm over all conditions
A Faraday shield post-process was introduced which enables the device to be tested at wafer and assembled in any package post-test just like a passive device
It was shown that this silicon die frequency source uniquely positioned for quartz replacement in several high-volume applications
Conclusions Quartz Replacement Silicon Die Freq. Source Applications Mobius and IDT
PAGE 34 of 34 www.IDT.com IEEE IFCS Newport Beach, CA USA June 2010
THANK YOU QUESTIONS WELCOME
Conclusions Quartz Replacement Silicon Die Freq. Source Applications Mobius and IDT