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Issue 41 April 10, 2012

Karen Bartleson Synopsys Electrical Engineering Community


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TA B L E O F C O N T E N T S TABLE OF CONTENTS

4

Karen Bartleson SYNOPSYS Interview with Karen Bartleson - Senior Director of Community Marketing; President-Elect of IEEE

9

An Effective Standard: The Unified Power Format BY KAREN BARTLESON Karen Bartleson walks us through her involvement in developing a technical standard to reduce power consumption in integrated circuits.

Featured Products The Right Processor for the Right Job

12 14

BY PAUL CLARKE WITH EBM-PAPST

How to simplify the harrowing process of choosing the right electronics device for your project.

Designing M2M Devices for First-Time Success

18

BY DERMOT O’SHEA WITH TAOGLAS

Dermot O’Shea outlines key development processes that will ensure a speedy time-to-market for your product.

RTZ - Return to Zero Comic

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INTERVIEW

How did you get into engineering and when did you start? Growing up, I didn’t even know what engineering was. I loved math and science, and I liked playing with dinosaurs and cars instead of Barbies. I guess I was just kind of weird. When I went to college, I was studying math and science, and The Society of Women Engineers (SWE) reached out to all the girls studying sciences. They said, “Why don’t you let us tell you what engineering is all about.” I was charmed. I thought, “Wow, this is really cool! Math, science, I get to make stuff— this is for me!” I was thrilled, so I switched my major. My first time entering the engineering school, I thought, “Where are all the girls?” “Oh God, what have I gotten myself into?” I was one of maybe two girls, and I was often the only girl in the class. My grades were better than almost everyone else’s in the class.

Synopsys Karen Bartleson - Senior Director of Community Marketing; President-Elect of the IEEE Standards Association

This was mostly because I liked the subjects and found the material fascinating, and I also found that the boys in the Engineering Department were generally polite, smart young men who were willing to study and work with me. It turned out to be an awesome career.

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In 1980, I started my first job. For engineers at that time, business was good. I had about half a dozen job offers to choose from, but I ended up choosing Texas Instruments (TI) because they were doing design automation, which combined hardware design and software engineering. My job was writing

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FEATURED INTERVIEW

Karen Bartleson


INTERVIEW

I just loved it! I was working on a new logic simulator, which, instead of modeling the transistor with just 1s and 0s, modeled different states such as tri-states, unknowns and floating. Of course, some existing engineers who saw these things thought it was weird, while others thought it was a great accomplishment. I actually got to go to Europe to introduce this new simulator. When I was in Italy, a group of TI engineers took me into a small conference room and everyone was smoking like crazy. Then they all started grilling me, saying things like, “Your simulator is terrible! We’ll never be able to use this!” Eventually they came around once I demonstrated to them its value. After a few years at TI, I became a manager while we were progressing very well with CAD. I later decided to move to Colorado to be close to my mom, and I took a job as CAD manager at United Technology’s Microelectronics Center (UTMC). There, we made radiationhardened ASICs designed to go into outer space and other harsh environments. My team’s job was to put together commercial CAD tools with internally-developed software and build the design system. After a while at UTMC, we were getting a lot of business because of our CAD system. Even though we manufactured some of the best ASICs for our market, our CAD system was better than our

competitors and customers were coming to us for our ASICs simply because of the reputation of our CAD system. I was very proud of that. Eventually, though, I got bored. I wanted to do more, and it was a small operation that wasn’t quite ready to put me somewhere else. I chose Synopsys because

Growing up, I didn’t even know what engineering was. I loved math and science, and I liked playing with dinosaurs and cars instead of Barbies. I guess I was just kind of weird. I admired their technology and superb engineers. At the time, Synopsys was viewed as a closed company in terms of its interfaces. But it was becoming a leader in electronic design automation (EDA) and realized that it needed to open up its interfaces because customers were demanding it. I was qualified to join the company because I knew how these interfaces worked and I knew the value of interoperability from a customer’s perspective. They hired me to be the Standards Program Manager, and my job was

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to get the company to open up and create industry standards. That meant that everyone at Synopsys hated my guts! Everyone said that I was going to enable the competition and put us right out of business. Fortunately for me and the company, that never happened. We continued to become a leader and our interfaces are now used widely throughout the industry. We’re also very proactive in the standards world. On a separate note, I was recently elected to become president of the IEEE Standards Association. I’m currently President-Elect, so I’m learning everything I possibly can from the current president before I take over for a two-year term for the years 2013 and 2014. For me, this is a really exciting career-enhancing and life-enriching experience. The Standards Association is one of the key standards-developing organizations in the world, which produces global standards for electricity and electronics. Can you tell us about the university program that Synopsys is associated with? Synopsys has had a university program since 1984. What we’ve done since then is turn the program into something much bigger and better than simply putting our software in universities. What a lot of companies do in their programs is give universities low-cost or free tools, which is neat because students gain practical hands-on experience, which better prepares them to enter the industry when they’re done with school. At Synopsys, we decided to do something even more valuable.

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FEATURED INTERVIEW

software that would automate the chip design—we called it computeraided design (CAD)—that’s how long ago it was.


INTERVIEW

We’re focusing a lot of attention on two fascinating areas. One of them is to help build high-tech industries in emerging economies. We go into a country that wants to develop its technology economy, and we work with the university system to incorporate new software and expand on the curriculum. This develops a new, well-prepared workforce at the student level. At the same time, we work with the government to help execute the operation. We’re working on reaching the ultimate goal where government, universities and industry come together to educate students so that they can move into the industry with the necessary skills and training to advance technology. We have had success with this in several countries such as Armenia, Jordan, Saudi Arabia and others. In Armenia especially, we have helped bring a high-tech economy, which boosts the standard of living throughout the country. We’re very proud of this from both a business and humanitarian perspective. It’s so great to think that an entire country will benefit from the work that we have done and are doing. The other area we’re focusing on is a unique Industry/University Educational Model. It’s exclusive to Synopsys; it’s like our own university, located in our own facility.

We go to engineering universities and pick the best students and bring them to our “university” to complete the last two years of their Bachelor, Master or PhD studies. We hire them as interns and teach them our specific curriculum: how to design EDA tools, how to design modern integrated circuits (ICs). It’s a very modern and valuable learning experience and at the same time, we put them to work. These students work in groups and have actually developed design kits for real technologies that are used by Synopsys customers with our products. So here are these young engineering students who are learning, while at the same time contributing to Synopsys customers by putting together these high-tech design kits.

Working with standards brings an incredible amount of respect and awe when you create something that is so widely used throughout the world—and that’s what engineers strive for. When the students graduate—after gaining this great experience—they

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will either go to work with one of our product business units and really hit the ground running as software engineers, or they will move into other positions with leading companies in the industry. This program is really the fast track to getting these students the most intensive and applicable learning experience possible. We are gaining from it by getting contributions from these amazing students, and they are gaining valuable education and experience. What are some of Synopsys’s philosophies associated with social media? Currently in EDA as well as the semiconductor industry, many people feel that social media is a waste of time that causes a decline in productivity. But times are changing and social media is becoming more and more useful for businesses. Synopsys has a progressive social media program that is designed to improve our productivity and the connections with our customers and partners. It helps us keep up with modern trends. Being a leader in technology, we try to transfer our leadership concept to what I call “marketing technology,” which is essentially what social media and social networks are. It’s really exciting for us to be right there on the leading edge of that technology as well—contributing to communication between engineers. To do this, we have created six channels. First is our corporate blog community, which has become a commonly accepted method of communication and is actively contributed to by subject matter experts who provide their expertise and post highly-focused information

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FEATURED INTERVIEW

We provide the universities with software tools as well as provide training for professors and educators, and we give them full support through our support center. For each university, we provide this program in full as if it were for a commercial customer. But we’ve taken it even further beyond that.


INTERVIEW before. For example, one day I was checking the Twitter feed and saw a post from someone that said, “Why do Synopsys tools suck so bad?” I looked up the poster and found out that he is indeed an engineer and a customer of ours. I thought, “This is bad,” So I contacted him and asked him what he was having a problem with, and he said, “Oh nothing really; I was just letting off steam.” I got to know him better and discovered that he did have an interest in standards, so we helped get him on a standards committee, which worked out well.

are effective, why they are important to an industry, and how to best go about creating them. A lot of times engineers will say things like, “Standards, oh man…First of all I don’t want to expose my technology, because it’s a secret and I don’t want anyone else to use it.” They also see standards as time consuming and highly political. They think that they don’t have the time because sometimes it can take two or three years to produce a standard, and they don’t like the politics because there is often a negative connotation associated with it in general.

We use social media for communicating and engaging in ways that are different from – yet still in support of – traditional marketing communications, which has worked out really well for us and our customers.

However, if you think about standards like Wi-Fi or USB—even with these other concerns in mind— you can see how standardization has had such an amazing impact on technology today. These standards grow the marketplace in a tremendous way.

Can you tell us more about your thoughts on standards? I wrote a book called The Ten Commandments for Effective Standards. In my experience, these are the 10 reasons why standards

Working with standards brings an incredible amount of respect and awe when you create something that is so widely used throughout the world—and that’s what engineers strive for. ■

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FEATURED INTERVIEW

for the world to see. The second channel that we have created is a radio show called Conversation Central. It’s on iTunes as well as our Web site, and every month we get an expert or two to talk with us for about half an hour about interesting topics, providing insight into the future of technology and business. We also have a Linkedin group with over 1,600 members contributing to technical discussions. Then comes Facebook, which is very interesting. We’re finding that half of the people who like our Facebook page are Synopsys employees, which tells me that our employees around the world want to interact with each other. After Facebook comes YouTube, where Synopsys has its own channel to which we regularly contribute. We have how-to videos and behind-the-scenes videos of conferences, both of which we’re really proud of because we expect the channel to really grow. Finally, the weirdest, and probably my favorite, is Twitter. We’ve had some amazing experiences on Twitter interacting with customers, in ways that I never would have been able to


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An Effective Standard: the Unified Power Format Karen Bartleson

Senior Director of Community Marketing, Synopsys; President-Elect of the IEEE Standards Association

Technical standards are pervasive. When they’re effective, they enable innovation, increase quality, and reduce costs. Over the past five years, I’ve been involved in a technical standardization effort that is a good example of an effective standard. It’s called the Unified Power Format, and its official name is 18012009 - IEEE Standard for Design and Verification of Low Power Integrated Circuits. Power consumption by electronic products – that is, the reduction of it – is one the most important challenges being addressed by the electronic design automation

industry. From mobile devices to massive data centers, lowering the amount of energy that their integrated circuits consume is essential to battery life, consumer satisfaction, cost and sustainability. There are two main types of power consumption within an integrated circuit: dynamic and leakage. Dynamic power consumption occurs when the integrated circuit’s components switch states, that is, from on to off and vice versa. Leakage power – also known as static power – consumption generally occurs when the components are inactive. (Some leakage power is consumed

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during switching, but it’s the wasted power used during inactivity that’s of most concern.) Two techniques are commonly used to reduce an integrated circuit’s power consumption: clock gating and multi-voltage threshold optimization. During clock gating, components that are not switching states are disconnected from the clock. (A “clock” is a distributed signal that controls the overall activity of the integrated circuit.) Clock gating helps reduce dynamic power consumption. With multivoltage threshold optimization, components that switch faster

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PROJECT Dynamic Power Consumption

Pstatic=V*I leak

Pdynamic=V*I sc+C*V 2*f ≈Ceff*V 2*fswitch fswitch=0.5*A*fclk

I leak

I sc I switch

Figure 1

and have more power leakage are replaced with components that are slower, but have less leakage (Figure 2). Advanced techniques for lower power consumption include multivoltage islands and power gating. Areas of the integrated circuit that can operate with lower power are isolated into “islands” that are supplied with lower voltages. This saves not only dynamic power but leakage power as well. During power gating, areas of the integrated circuit that are idle at times are completely shut down, preventing leakage (Figure 3).

Today, UPF is undergoing updates and enhancements within the IEEE Standards Association in the “P1801” project working group. It continues to serve the industry well as we design ever-more-complex integrated circuits that demand less power. When low-power design techniques were originally developed, design

Clock Gating

CLK

FF

ICG

The industry stood up and demanded a common format be created and standardized. The result was the Unified Power Format, UPF. Eight donations of proven technologies from seven companies were merged into a single standard format. Because the industry moves at the speed of Moore’s law – integrated circuits doubling in complexity about every

Multi-threshold

D EN

engineers from different companies wrote their design intent in formats that they created themselves. Suppliers of design automation tools that converted design intent into low-power component structures also invented their own formats for describing design intent. These formats weren’t the same from company to company nor from supplier to supplier. This put a burden on design teams who needed to communicate lowpower design intent with each other and provide the information to automation tools. It also put a burden on design automation suppliers who needed to support different formats and weren’t necessarily allowed to use competitors’ formats. Converting low-power information among various formats was resource-intensive and errorprone.

Q Leakage current

Static Power Consumption

Engineers who work on aspects of an integrated circuit’s power consumption – striving to reduce it as much as possible while meeting performance requirements – start with a plan, called “design intent,” that details how the integrated circuit can take advantage of the low-power design techniques described above.

Low VTH

Nominal VTH High VTH Delay

Figure 2

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FEATURED PROJECT

Total Power


PROJECT

Today, UPF is undergoing updates and enhancements within the IEEE Standards Association in the “P1801” project working group. It continues to serve the industry well as we design ever-more-complex integrated circuits that demand less power. ■

OFF

1.2V 1.0V 0.9V

FEATURED PROJECT

1.5 years – the standard had to be completed quickly. In less than six months, UPF was ratified by the standards-setting organization, Accellera, and transferred to the venerable IEEE to go through its formal standardization process.

1.2V 1.2V

Figure 3

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F E AT U R E D P R O D U C T S Atmel® Corporation, a leader in microcontroller and touch technology solutions, announced that it is sampling to select customers XSense™, its revolutionary, highly flexible film-based touch sensor. XSense touch sensors will not only enable a new generation of smartphones and tablets, but also extend touch capabilities into a wider array of new consumer and industrial products. Based on a proprietary roll-to-roll metal mesh technology, XSense touch sensors provide a high-performance alternative to existing touch sensors. Original equipment manufacturers (OEMs) will now be able to develop larger, lighter, sleeker, curved and edgeless designs for smartphones, tablets, Ultrabooks and a host of new touch-enabled products. For more information, please click here.

Fast Settling Time ADC Driver Texas Instruments Incorporated has redefined the low-power amplifier market with today’s introduction of a fully differential analog-todigital converter (ADC) driver that provides more than eight times the performance-to-power ratio of similar devices. The THS4531 fully differential amplifier uses only 250 uA of quiescent current while providing 36 MHz of bandwidth to support the high-performance, ultralow power needs of portable and high-density systems, such as flow meters and portable medical devices. For more information, please click here.

VIN +50V

+50V

+

Optional 3.3V regulator

Power over Ethernet IC for Surveillance Systems

Silicon Laboratories Inc., a leader in high-performance, analog-intensive, mixed-signal ICs, today introduced a single-port Power over Ethernet (PoE) controller that brings economical “plug-and-play” simplicity to embedded power sourcing equipment (PSE) designs. The new Si3462 controller eases the development of PSE endpoints such as residential gateways, set-top boxes, fiber-optic media converters, and surveillance and security systems that connect to a wide variety of powered devices including VoIP phones, security cameras, keypads, network attached storage and WiFi access points. Powered devices (PD) continue to proliferate in small office/home office (SOHO) and small-tomedium business (SMB) markets, driving the need for easy-to-use single-port embedded PoE/PoE+ PSE solutions to enable these end devices. With the rising popularity of the higher power IEEE 802.3at PoE+ standard and the need to support PD applications that consume up to 30 watts, developers require PSE controllers that offer flexible power measurement and monitoring capabilities, standards-compliance and no interoperability hassles.For more information, please click here. VDD +3.3V

Detect & Mark

VDD

Si3462

GND

GND

Classification (Optional) and Gate drive

DETA VSENSE ISENSE STATUS

RST

GND

CLSMARK DC1 DC2 CLSMODE

DETECT FAULT PGOOD

VOUT 48 V

PSE output (to port magnetics)

-

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FEATURED PRODUCTS

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The Right Processor for the Right Job Paul Clarke

Electronics Design Engineer

Over the years, microprocessors and microcontrollers have changed significantly. We can now do more, quicker and in ever-smaller packages. However, with so many devices available, which one should you use? This is a question I noted that most people don’t really consider. I spend time on electronics forums and see people making some very odd selections. I’ve helped were I can, but often found myself saying the same thing over and over again – “The right processor for the right job”. Electronics engineers are extremely careful when it comes to selecting the right FET or relay. We don’t just pick the first capacitor we find in the catalogue for the job either. All electronics devices have pros and cons that are carefully considered

Figure 1

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TECHNICAL ARTICLE

It’s no jump at all then to consider a microprocessor or microcontroller as anything other than just a electronics device. However, people do not always look at the impact of their choices—the issue seems that people get caught up by one of two things; being comfortable or being too geeky! Many chips find themselves moving from product to product or from one hobby project to the next because at some point, the engineer has dealt with some messy set-up and has decided to transplant the same chip. This has the advantage of being quick to set up and get you off the ground and going. However, there is almost no consideration taken to if, for example, the chip has enough I/O. I then find people trying to shoehorn in applications to limit memory or needing vast amounts of I2C bus extensions to connect EEPROMS, RTCC or just plain IO. It’s worrying how far some people will go to keep working with the same chip because they are comfortable with it. The geeks among this family of chip selectors have very different ideas. It’s not hard to spot them—they have the latest iPhone or super fast gadget and never really use it – they are the must-have-it people. They will see new chips like the ARM Cortex-M4 and look for something to design with it. These people have to have the fastest, most powerful 32bit chip running a RTOS and using DMA to PWM control the brightness of a LED. Unfortunately, using the latest and fastest is just

following the old saying of using a sledge hammer to crack a nut. They are way too powerful and expensive and if you code it using less than 3% of code space ask yourself what you are doing. There are, however, many factors in selecting the right chip and these are just some of the ones I consider every time! I don’t believe that you can use the same chip over and over, which also extends to the manufacture too. At ebm-papst, where I work, it’s been a longterm decision to use microchip devices. These come in a massive range from small 6pin 8-bit chips up to massive MIPS 32-bit cores. This has given us an advantage of using one IDE over time and we have one support contact and core supplier of the devices. It’s been a good choice to stay with one manufacturer, however, our projects have had very common themas. We have only used 8-/16bit devices because these were quick enough, low cost and had the right built-in features. As we move forward and start considering 32-bit devices, we have found that maybe the Microchip family is not for us. As such, I’m now considering NXP Cortex-M0s and M1’s. Consideration for cost, amount of I/O and the type of I/O is paramount. Things like I2C, SPI and numbers of UARTS are all to fit your application, not the other way round. Memory and code space are also very important but a key feature that can swing lots of people is the IDE and support tools. Support tools are very important, as these can either make your project a joy or the job from hell.

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So when it comes to considering a chip, I take a blank sheet of paper and, leaving a gap in the middle, start laying out what I/O I need and blocks with things like Modbus, display interface, number of fans, sensor inputs, GPS or anything else you can think of. I then look at the number of I/O lines and the type of interface I need. You need to consider moving stuff around. For example, if you have two I2C devices already, could you move that SPI EEPROM to a I2C bus? Or would that interrupt your bandwidth to the high spec ADC that’s on the I2C bus? Consider where I/O works best. After this, you can then make a grid of all the interfaces you need down one side. Consider from experience how much code and RAM you will need. Block out a flow chart of your code if you have to—it helps to get a better estimate. I would also set limits, like what I would like and what is essential. Along the top, you can place the device name / part number and start filling in what it has to offer. I colour numbers in green that meet the spec and red for ones that don’t. It’s then very easy to see which chips you should consider. Some chip manufactures do help with this selection, however. The microchip selection tool is interactive so you can adjust your options and see what chips are available.

It’s now down to you. You have to decide which one you are most happy with. But the important thing is that you are making a choice. If

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TECHNICAL ARTICLE

as well as parametric details, lead times and cost—all of which contribute to our decisions.


TECHNICAL ARTICLE TECHNICAL ARTICLE

Figure 2

you are choosing a chip, that means a new IDE and support tools, which is for the good of the project. Remember, you’re an engineer and love solving problems. Selecting the right chip and defending that choice with your peers means that you have stopped pushing square pegs in round holes. http://www.microchip.com/prod-

uctselector/MCUProductSelector. html About the Author Paul Clarke is a digital electronics engineer with strong software skills in assembly and C for embedded systems. At ebm-papst, he develops embedded electronics for thermal management control solutions for the air movement industry.

He is responsible for the entire development cycle, from working with customers on requirement specifications to circuit and PCB design, developing the software, release of drawings, and production support. â– 

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Get the Datasheet and Order Samples http://www.intersil.com

Low-Noise 24-bit Delta Sigma ADC ISL26132, ISL26134

Features

The ISL26132 and ISL26134 are complete analog front ends for high resolution measurement applications. These 24-bit Delta-Sigma Analog-to-Digital Converters include a very low-noise amplifier and are available as either two or four differential multiplexer inputs. The devices offer the same pinout as the ADS1232 and ADS1234 devices and are functionally compatible with these devices. The ISL26132 and ISL26134 offer improved noise performance at 10Sps and 80Sps conversion rates.

• Up to 21.6 Noise-free bits.

The on-chip low-noise programmable-gain amplifier provides gains of 1x/2x/64x/128x. The 128x gain setting provides an input range of ±9.766mVFS when using a 2.5V reference. The high input impedance allows direct connection of sensors such as load cell bridges to ensure the specified measurement accuracy without additional circuitry. The inputs accept signals 100mV outside the supply rails when the device is set for unity gain.

• On-chip temperature sensor (ISL26132)

• Low Noise Amplifier with Gains of 1x/2x/64x/128x • RMS noise: 10.2nV @ 10Sps (PGA = 128x) • Linearity Error: 0.0002% FS • Simultaneous rejection of 50Hz and 60Hz (@ 10Sps) • Two (ISL26132) or four (ISL26134) channel differential input multiplexer • Automatic clock source detection • Simple interface to read conversions • +5V Analog, +5 to +2.7V Digital Supplies • Pb-Free (RoHS Compliant) • TSSOP packages: ISL26132, 24 pin; ISL26134, 28 pin

Applications

The Delta-Sigma ADC features a third order modulator providing up to 21.6-bit noise-free performance.

• Weigh Scales

The device can be operated from an external clock source, crystal (4.9152MHz typical), or the on-chip oscillator.

• Temperature Monitors and Controls

The two channel ISL26132 is available in a 24 Ld TSSOP package and the four channel ISL26134 is available in a 28 Ld TSSOP package. Both are specified for operation over the automotive temperature range (-40°C to +105°C).

• Pressure Sensors

• Industrial Process Control

CAP

AVDD

DVDD

INTERNAL CLOCK

EXTERNAL OSCILLATOR

XTALIN/CLOCK XTALOUT

AIN1+ AIN1AIN2+ AIN2AIN3+ AIN3-

SDO/RDY INPUT MULTIPLEXER

PGA 1x/2x/64x/ 128x

ADC SCLK

ISL26134 Only AIN4+ AIN4PWDN

SPEED

A0

A1/TEMP AGND

GAIN0 GAIN1

CAP

DGND

VREF+

VREF-

DGND

DGND

NOTE for A1/TEMP pin: Functions as A1 on ISL26134; Functions as TEMP on ISL26132

FIGURE 1. BLOCK DIAGRAM

September 9, 2011 FN6954.1

Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2011 All Rights Reserved. All other trademarks mentioned are the property of their respective owners.


Designing M2M Devices for First-Time Success Dermot O’Shea

Co-Founder and Joint Managing Director of Taoglas

Radio frequency (RF) optimization and over-the-air (OTA) performance in wireless devices is critical for network certification and PCS-1900 Type Certification Review Board (PTCRB). There are many reasons why M2M devices fail certifications, and antennas are often to blame for certification failures. This can be due to the antenna itself, an incorrect antenna selection, or the way it is integrated. Often it is a system issue, such as the overall design of the system and how that device is interacting as a system. In this article I will discuss the important process of antenna selection, how to incorporate them in M2M devices, and the recipe for connectivity success. First, let’s take a look at selecting the proper antenna.

Early Antenna Selection Paves the Way for Success Understanding the requirements for achieving certification such as PTCRB and specific network certification processes are the most important factors when first selecting an antenna. Once the module provider and the carrier have been selected, the next part of the process should be selecting the right antenna for your application. This will have a significant impact on the size, layout and performance of your device. Hence, it is important to make your selection at the early stage of the design. This will enable the antenna provider to consider the application, target performance, certification requirements and device topology when advising on the most relevant antenna solution.

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TECHNICAL ARTICLE TECHNICAL ARTICLE

Figure 1: Inside of the Anechoic Chamber

Antenna selection and integration will affect over-the-air (OTA) requirements and can affect radiated spurious emission (RSE) figures. Without high antenna efficiency, certain network OTA requirements—particularly Total Radiated Power (TRP)—will not be met. RSE is a common point of failure for machine-tomachine (M2M) devices seeking PTCRB certification. This can be misinterpreted as an antenna issue. Here’s what can happen: 1. RSE failure can be caused by an antenna impedance mismatch with the module when the device is on and transmitting.

The solution is to design the antenna for an active device, not just a passive device. There must be a good impedance match when the device is on and transmitting and when connected to the network/base station simulator. 2. When the antenna selection is good and efficiency is high, the total radiated power (TRP) will be high. This is exactly what you want to achieve for optimal send and receive sensitivity. However, this can also result in the system re-radiating emissions, and with the increased power, RSE failures can result. It is not

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good practice to detune the antenna or bring down antenna efficiency to resolve this issue. The emission source needs to be identified and eliminated, or at least prevented from getting to the antenna and being received into the system. Following Best Practices Delaying antenna decisions can result in the loss of the device’s window of opportunity in the market and will end up costing hundreds of thousands of dollars in device debugging and/or redesign, not to mention additional testing and certification fees.

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1. Plan for problems. Wireless device design is complex, especially when multi-band cellular is included, and even more so when other wireless technologies such as GPS, WiFi, 915MHz and others are present. The presence of batteries and other metals close to the cellular antenna can cause issues in any system. Devices using an embedded antenna are likely to require some level of customization. Many M2M companies are not experienced in wireless device design to debug design issues, and may not have access to the equipment and resources to acquire this expertise. Many years of experience on similar products is what enables engineers to quickly identify and resolve issues that cause RSE failure. 2. Separate antennas. Keep the antennas as far away from each other as possible to avoid detuning issues. 3. Size matters. The bigger the antenna, the better the antenna. Size enables antennas to have wider bandwidth, more gain and better efficiency. The more space allocated for a cellular antenna, the easier it will be for the antenna designer to deliver a successful solution. The same rule applies to antenna clearance.

4. Avoid cables and connectors. Cables and connectors should come with a warning note. They introduce loss and can bring impedance mismatches. This is unavoidable if external antennas are required, but an edge-mounted connector can be used with a transmission line to route the signals to the module. This is more effective than a cable jumper.

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5. Target with margin. It is best to target with a 2dB margin. That way, if problems do occur, it does not affect the test plan.

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6. Optimize shielding. Try to implement physical shielding on the PCB as much as possible. The simplest way to achieve this is to place metal cans over active circuitry. 7. Completely fill your ground plane. It is best to fill in all unused areas of your printed circuit board (PCB) with ground. 8. Test the antenna. It is important to perform proper antenna testing (return loss and efficiency) during the initial design and prototype stages. At the final stage, it is vital to measure antenna efficiency and perform OTA and RSE prescans. 9. Consult with experts. Talk to all the relevant parties regarding your application—the carrier, module provider, antenna provider, test labs and design house. A design review is also recommended before finishing hardware design.

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The bottom line for ensuring quick development, speedy time-tomarket and ease free certification for M2M devices is planning well ahead. Getting the antenna right is easy if you begin early and integrate antennas into the design as one of the first steps. My advice is talk to the experts early and frequently; it will save a lot of money in the long run.

Dermot O’Shea is co-founder and joint managing director of Taoglas. Having founded Taoglas with Ronan Quinlan in Taiwan in 2004, he is currently responsible for sales, finance and marketing and is based in Taoglas’ San Diego office. Prior to founding Taoglas, Dermot worked for over ten years in the global electronics industry for companies such as Network International. He is a highly regarded source in the M2M antenna market and today advises automotive, tracking, telemedical and utility companies worldwide on antenna solutions. Dermot is an expert in the wireless antenna arena, he provides high-level counsel on device noise debugging, testing services, device certification and approval management. Dermot has a Science Degree from University College Dublin and postgraduate diplomas from Dublin Business School (Business), Griffith College Dublin (Computing) Waterford Institute of Technology (Enterprise Development). For more information visit: http://www.taoglas.com ■

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EEWeb Pulse - Volume 41