EDN Magazine Issue 2010-01-21

30.7 MB·English

by  Reed Electronics Group

( )
®
21 Extending electronics’
life span Pg 13
JAN EDN.comment Pg 6
IssIusseu e21 2//22000150 Jitter and the ins and
wwwwww..eeddnn..ccoomm outs of SNR Pg 14
Prying Eyes:
Analyzing a NAS Pg 16
Design Ideas Pg 31
VOICE OF THE ENGINEER Brown’s buzzer busts
business Pg 40
INTEGRATION IN
THE OTHER
DIRECTION
Page 24
RECOGNIZING
TECHNOLOGY’S
INFLECTIONS
Page 19
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Enter xx at www.edn.com/info
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1.21.10
contents

OOOOOOOOOOOOOOOOOOOOO
Integration in the other direction
24Building your system with separate
dice or separate chips may be a smart

alternative to using SOCs.
by Paul Rako, Technical Editor
OOOOOOOOOOOOOOOOOOOOOOOOOO

pulse
Dilbert 10

OOOOOOOOOOOOOOOOOOOOOOOOO
Recognizing
9 High-performance scopes 12 Solid-state-drive countera ttack
technology’s
provide 20-times boost packs a two-part punch
in waveform-update rates inflections
12 Processor pushes power
10 Tiny PV cells offer even lower 19Inflections involve
big benefits improving perform-
13 Voices: iFixit’s Kyle Wiens:
ance, cost, or both. More
11 Energy harvester targets extending electronics’ life
important, they simplify sys-
piezoelectric transducers span
tems for their users.
11 Cadence Virtuoso release by Robert Cravotta,
highlights usability Technical Editor
D E S I G NI D E A S
5V 31 Excel spreadsheet measures analog voltages
MCAPD3C201 (cid:1)1C (cid:2)1F DB25 CLOPNTN1EC32 Schottky diodes improve comparator’s transient response
8
12VINR(cid:1)EF DOCUST5615BBIITT 73 OOFF 00xx337789 9 34 Algorithm keeps data safe
3IN(cid:1) CLK78BIT 6 OF 0x378
4 24 36 P-channel power-MOSFET driver uses unity-gain op amp
2 EDN | JANUARY 21, 2010
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29
More Q. Less Cu
Copper
63.546
These tiny new air core inductors
have the highest Q and current handling
in the smallest footprint.
Coilcraft’s new SQ air core inductors have unmatched Q
factors: most are above 200 in the 1-2 GHz range! That’s 3
times higher than comparably sized 0805 chip coils.
And with their extremely low
DCR, they can handle 4 to 8 times
more current: up to 4.4 Arms.
SQ air core inductors are perfect
for your LC filter and RF impedance
matching applications. They come in
15 values ranging from 6 to 27.3 nH,
Q factors are 3X higher than all with 5% tolerance.
standard chip inductors
These coils
are significantly smaller than exist-
ing air core inductors. We reduced
the footprint by using close-wound
construction and keeping the leads
close to the body. The square shape
cuts the height to as low as 1.5 mm
and creates flat top and bottom sur-
faces for easy automated handling
and stable mounting.
See how the ultra-high Q and
current handling of Coilcraft’s
The square shape and narrow footprint
reduce board space by 60-75% over new SQ air core inductors can
conventional air core inductors. maximize the performance of
your next design. For complete specifications and free
evaluation samples, visit www.coilcraft.com/sq
®
RoHS
CCOMPLIANT
www.coilcraft.com 800/322-2645
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contents
1.21.10
Simpler Power
Conversion
IR’s AC-DC product portfolio
offers simple, compact high
density solutions tailored
16 40
for energy-effi cient
power supplies.
D E PA R T M E N T S & C O L U M N S
6 EDN.comment: IP networks’ spread brings challenges
to networking SOCs
14 Baker’s Best: Jitter and the ins and outs of SNR
16 Prying Eyes: Analyzing a NAS
39 Product Roundup: Optoelectronics and Displays
40 Tales from the Cube: Brown’s buzzer busts business
µPFC™ PFC IC
online contents www.edn.com
PNaurmtber Pckg. V(VCC) (FkrHeqz). DG±ra(iAvte)e CVl(aGVAm)TEp CMurordeent
ONLINE ONLY PRYING EYES I(RS1T1R5)0PbF PSDOI-P88 13-22 50-200 1.5 13 CCM
Check out these Web-exclusive articles:
In EDN’s Prying Eyes, we peer inside an
Reduce handset EMI to prevent receiver-
desense problems end-user consumer gadget, a reference SmartRectifier™ IC
design, or any other interesting electron-
You can solve cell-phone EMI (electromag-
ics-enabled thing we can get a good look Part IR1166S IR1167AS IR1167BS IR1168S
netic-interference) problems with disciplined Number PbF PbF PbF PbF
at. Prying Eyes aims to illuminate the tough
t➔rowubwlew-.eshdono.ctoinmg/ taerctihcnleiq/uCeAs6.711838 design decisions the engineers responsible Package SO-8
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Determine your IC’s transient thermal Prying Eyes archive at www.edn.com/ VFET (V) <=200
behavior to prevent overheating pryingeyes, or sample a couple of install- Smwax F (rkeHq.z) 500
ments at the links below:
Use Spice to determine the thermal time G±(aAte) Drive +1/-4 +2/-7 +1/-4
constants of the IC package. The Zune’s HD: more than an iPod
www.edn.com/article/CA6713633 touch wanna-be? (VVG)ATE Clamp 10.7 10.7 14.5 10.7
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Peering into ultrasound machines M(nsin). On Time Program. 250 -3000 750
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,,
EDN.COMMENT
BY RON WILSON, EXECUTIVE EDITOR
pattern still exists where functions oc-
cur in the network, according to Eric
Hayes, Broadcom’s senior director of
product marketing. “At the edge, poli-
cy is user-based and generally oriented
toward security concerns,” he says. “As
you move nearer the core, policy be-
comes more QOS-oriented. So while
we have a uniform programming mod-
IP networks’ spread brings el across the families, the ability to ap-
ply policy varies from chip to chip.”
challenges to networking SOCs Switch-fabric vendors aren’t the
only ones to see a growing common-
ality across applications. NPU (net-
P
erhaps the most pervasive trend in networking today is work-processing-unit) vendor Xeler-
the seemingly complete victory of IP (Internet Protocol) ated has been successfully serving the
over rival protocols and the concomitant spread of GbE mobile backhaul market but finds fi-
ber-access applications increasingly
(gigabit Ethernet). GbE is replacing other alternatives and
attractive, says Thomas Eklund, Xel-
even packetizing legacy data flows and carrying them as
erated’s vice president of marketing
encapsulated IP traffic. Along with carrying the traffic, and business development. Both mar-
the new fast networks also must provide the application-specific services kets face similar QOS issues but from
that older networks have evolved. This trend is drawing together dispa- different sources.
In the backhaul market, ATM
rate networks into a single medium, vastly simplifying facilities manage-
(asynchronous-transfer-mode) net-
ment for network operators but creating a pain for silicon designers.
works often handle latency-intolerant
The highest-profile example may be Requiring all these time-domain-multiplexed voice traf-
in data centers, in which a 10-Gbit Eth- fic. In that market, the challenge is
functions becomes
ernet fabric is drawing in three physi- how to handle the increased data ser-
cal networks: InfiniBand for clustering, a serious challenge vices that smartphones demand and
Ethernet for data, and Fibre Channel that LTE (long-term evolution) prom-
for SOC designers.
for storage. The convergence means ises. In fiber-access networks, built for
that the single network must offer all sporadic and latency-insensitive Web
the management and QOS (quality- segment at Broadcom. The need for browsing, the problem is IPTV. Both
of-service) features that three kinds of features, including MPLS (multipro- applications now seem to be converg-
networks formerly provided. That sce- tocol label switching) and time syn- ing on similar needs for management
nario, in turn, has implications for net- chronization, is cropping up across ac- and QOS, and those needs look a lot
work-adapter cards, classifiers, and fab- cess, backhaul, and aggregation net- like carrier-Ethernet specifications.
rics throughout the network. works, he adds. Switches throughout A parallel between the two conver-
The same process seems to be unit- the network essentially must support gences exists in data centers and in
ing the various networks that serve us- carrier-class services. the global network, which, in the long
ers of the Internet. In the past, local Requiring all these functions across run, may foretell an evolution to an
networks for end users, the aggrega- such a range of price and performance architecture that distributes comput-
tion networks, fiber-access networks, becomes a serious challenge for SOC ing and storage resources throughout
and mobile backhaul networks all had (system-on-chip) designers. The high- one network. In the meantime, SOC
distinct requirements. According to end switches may require dedicated designers will be busy enough figuring
at least two semiconductor vendors, hardware and substantial memory to out how to assemble and lay out the
however, all of these networks may meet the demands of, for example, optimum family to spread a new level
be converging. “We are seeing a need MPLS at wire speed. Yet low-end of classification and routing services
for a common feature set at several switches go into cost-sensitive mar- across a lot of legacy applications.EDN
different layers of the network,” says kets and can’t carry a silicon overhead
Jim McKeon, senior manager of prod- for performance they don’t need. Contact me at ronald.wilson@reed
uct marketing for the service-provider Fortunately for chip designers, a business.com.
6 EDN | JANUARY 21, 2010
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