ELECTRONIC INTERFACE FOR EMF KEYBOARDS · 2001-09-12 · Application Experiment No 23597 30.12.1998...

FUSE DEMONSTRATOR DOCUMENT

Application Experiment Number 23597

ELECTRONIC INTERFACE FOREMF KEYBOARDS

Screentec KySatamatie 2FIN-90520OULUFINLAND

Application Experiment No 23597 30.12.1998

ABSTRACT.......................................................................................................................31. COMPANY NAME AND ADDRESS .......................................................................................42. COMPANY SIZE.............................................................................................................43. COMPANY BUSINESS DESCRIPTION....................................................................................44. COMPANY MARKETS AND COMPETITIVE POSITION AT THE START OF THE AE.............................55. PRODUCT TO BE IMPROVED AND ITS INDUSTRIAL SECTORS .....................................................66. DESCRIPTION OF THE TECHNICAL PRODUCT IMPROVEMENTS...................................................97. CHOICES AND RATIONALE FOR THE SELECTED TECHNOLOGIES, TOOLS AND METHODOLOGIES.....118. EXPERTISE AND EXPERIENCE IN MICROELECTRONICS OF THE COMPANY AND THE STAFF ALLOCATEDTO THE PROJECT ..............................................................................................................149. WORKPLAN AND RATIONALE .........................................................................................1410. SUBCONTRACTOR INFORMATION ...................................................................................1611. BARRIERS PERCEIVED BY THE COMPANY IN THE FIRST USE OF THE AE TECHNOLOGY................1812. STEPS TAKEN TO OVERCOME THE BARRIERS AND ARRIVE AT AN IMPROVED PRODUCT ...............1913. KNOWLEDGE AND EXPERIENCE ACQUIRED ......................................................................2014. LESSONS LEARNED .....................................................................................................2115. RESULTING PRODUCT, ITS INDUSTRIALISATION AND INTERNAL REPLICATION ........................2216. ECONOMIC IMPACT AND IMPROVEMENT IN COMPETITIVE POSITION.......................................2417. TARGET AUDIENCE FOR DISSEMINATION THROUGHOUT EUROPE ..........................................26


Abstract

Screentec Ky is a company located in Oulu, Finland, whose main business area is inmembrane keyboards and related interface electronics. Screentec was founded in 1988and it employs now 25 people. The turnover in 1997 was 10 million Finnish marks.The company has developed a new technology for manufacturing keyboards toapplications which require good resistance against vandalism and outdoorenvironment. The technology is based on Electromechanical film, EMFi, a thin, elasticelectret film, which generates a charge signal when pressed.

The existing products of Screentec are keyboards consisting of EMFi elements andinterface electronics installed in a protective cover made of materials such asaluminum, steel and plastics. The interface electronics for the existing products havebeen realized using PCB with standard surface mount components.

The objective of the AE was to design and manufacture a Full Custom Mixed SignalASIC, which includes all the interface electronics required for a 16 key element. Therationale was to improve the competitiveness of the product by decreasing theproduction costs. The main benefits of the ASIC are the lower production andcomponent costs of EMFi keyboard, totaling in 50% saving in the electronics and 35%saving on the whole product. The product will also be smaller and more reliable.

During the experiment we have learned about the technical and economical aspects ofusing ASICs. We have learned how to specify an ASIC and the basics of analog anddigital ASIC design by designing ourselves functionally the analog and the logicsections of the ASIC. We have also learned about the design and NRE costs and thecost savings possible with ASICs. This ASIC and the experience gained during thisproject are very useful to us because there are several other applications of EMFi,which have the potential to become mass volume products.

The cost of the AE was 100 000 ECU and the duration was 12 months. Theexperiment started on 1.11.1996 and ended on 30.10.1997. We believe to reach theannual production volume of 25.000 pieces by year 2001. The investment will be paidback in 26 months. The Return on Investment calculated over the 6 years lifetime ofthe ASIC is average 39% annually.

The project succeeded according to plans and it showed that with good planning andright partners even a First User can get a mixed signal ASIC right first time. After thisproject we have a new version of the 16 key keyboard which is cheaper and easier toproduce and which offers new features for configuring the keyboard output.


1. Company name and address

Screentec KySatamatie 2FIN-90520 OULUFINLAND

2. Company size

Screentec is a privately owned company and it is not a part of any parent company.The number of personnel employed is 25 and four of them are involved in electronics.The turnover in 1997 was 10 million Finnish marks.

Screentec has over 10 years of experience in manufacturing membrane keyboardsand related electronics and is known as a pioneer in this field in Finland.Screentec’s staff has experience in designing various analog and digital electroniccircuits and PCBs using both through hole and surface mount components.Screentec did not have any prior experience in ASIC technology before the AE.Neither did we have experience of using CAE tools in the design.

In this project 2 electronics designers and 2 assembly persons were involved. Thedesign engineers were:

Mr. Lasse Räisänen R&D ManagerMr. Keijo Kiirikki Electronics engineer

3. Company business description

Screentec’s main business area is design and manufacturing of custom membranekeyboards, user interfaces and related electronic circuits. These products formed90% of our turnover in 1998. These products are designed for the devicesmanufactured by our customers in different industrial sectors, such astelecommunications, medical technology and industrial process control.Marketing of the products is mainly done by our marketing office located inHelsinki, but persons involved with the design of products also take part inmarketing. Installation and maintenance of the products is in most cases done bythe customer. Screentec has a rather large number of customers and the largestcontribution of one customer to the turnover has normally been less than 20 %.

During the last three years Screentec has invested into research and developmentof a new technology, the Electromechanical Film, EMFi. This technology makesit possible to manufacture keyboards which can endure abusive use and harshoutdoor environment. There is a growing need for this kind of ”vandal proof”


keyboards in various public places, such as mass transportation stations andvehicles, cash machines and other similar machines. We apply EMFi technologyalso for manufacturing various sensor applications to our customers, such aspickups for musical instruments and different force sensors. The EMFi basedproducts formed 10% of our turnover in 1998.

Figure 1. Vandal-proof keyboard.

4. Company markets and competitive position at the start of the AE

Screentec’s main business area is design and manufacturing of customizedmembrane keyboards, user interfaces and related electronic circuits. Screentec isthe biggest manufacturer in Finland in this area with some 40% of this market.The most important Finnish electronics companies are our customers. Thecustomers are mainly in the following areas:

• telecommunications• mobile phones• hospital electronics• machine and equipment manufacturing

Custom keyboards are typically manufactured locally and at present Screentecdelivers mainly to Finnish companies. We have 3 main competitors in Finland.Foreign competition is seen mainly in very high volume applications. The marketfor membrane keyboards in Finland is about 20 million FIM. Screentec’s goal isto maintain the present strong position in Finland in the membrane keyboardarea. There are no particular plans to invest in exports with these products. Theopportunity to grow and increase exports is in vandal proof keyboards.

There are lots of small manufacturers of custom membrane keyboards throughoutEurope. There are also some larger companies like C&K, EMCOS, RAFI,


SECME and TEMIC. The market is fragmented and no one has a market sharegreater than 20%. The European market is estimated to be 0.5 - 1 billion ECU.

In vandal proof keyboards Screentec has entered the market with smallkeyboards with 3 - 6 keys. The larger keyboards have not yet gained a noticeablemarket share, because the production costs for the present electronic interface aretoo high. This AE will help us to bring down the cost of our vandal proof 16 keykeyboard and improve the manufacturability, functionality and performance ofthe keyboard. The component and production costs of the electronics partdecrease from 20 ECU to 10 ECU. This cost reduction will help us to reach 1%of the European vandal proof keyboard market in year 2000. The long termtarget is to reach 5% market share in Europe.

The market for vandal proof keyboards is estimated to be 100 - 150 MECU inEurope in 1998. The main competitors in vandal proof keyboards are Schurterfrom Germany, Makashi from Israel and Grayhill from USA. The vandal proofkeyboards are a small segment of the total keyboard market, which makes itdifficult to get precise market information on this segment.

5. Product to be improved and its industrial sectors

The existing product is a keyboard for heavy use based on EMFi technology.Number of keys varies depending on the application, typically it is 16 or less. Itconsists of an EMFi element and the interface electronics which are epoxymolded inside a protective cover made of aluminum or other durable materials.The keyboard has one digital pulse output for each key of the keyboard. Thepresent technology does not allow other output options like matrix coded 4x4 orserial RS232.


Figure 2. Aluminum front cover for a 16 key EMFi keyboard. The size is 12 x12 cm and the thickness is 12 mm.

Pressing the cover at the location of one of the key electrodes generates anelectric charge to the electrode at that location in the element, and this charge isconverted to a voltage signal by a preamplifier circuit connected to that electrode.The preamplifier circuit is followed by a comparator circuit, whose outputshows a pulse if the voltage signal exceeds a certain threshold level.

Figure 3. Function.

The EMFi element is designed so that charge is generated to a key electrode onlywhen the cover is pressed at the exact location of that key electrode; signalgeneration when pressed for example between two keys is prevented by a specialmask layer in the element. The charge generated is directly proportional to thechange of the thickness of the EMFi.

Cover Material AluminumCover Thickness 1 - 4 mmActivation Force Adjustable 1 - 10 NSwitch Action One ShotPulse duration 50 - 500 msOutput low level (at 1mA)

< 0.5 V

Output high level (at 1mA)

> 0.9 VDD

Operating voltage VDD 5 V 10%

Supply current 10 - 15 mAOperating Temperature - 40 oC to + 65 oCCycles > 1 000 000Protection System IP 68Shock resistance 1000 g

Table 1. EMFi 16 key keypad functional specification

The interface electronics (block diagram below) needs charge sensitivepreamplifier circuits, capable to detect the small charge generated by the EMFi


when the cover is pressed lightly with a finger at the location of some keyelectrode. The existing interface electronics have been made using standard PCBswith surface mount operational amplifiers. Expensive high quality operationalamplifiers must be used. The electronics for 16 keys is fully analog and consistof 9 IC circuits, 42 resistors and 18 capacitors on a double sided 8x8 cm PCB.

Figure 4. Block diagram of the existing electronic interface.

The interface has one analog input and one digital output for each key. Theprincipal schematic of one channel is shown in figure 4.

Figure 5. Schematic of one key signal path

The charge obtained from the EMFi key varies from 5 to 100pC depending onthe keyboard construction and the force pressing the key. Detecting such a smalland widely varying charge requires high quality operational amplifiers and highvalue resistors to be used. The offsets of the operational amplifiers used have tobe small and they should match with each others in order to maintain similarcharacteristics for each key.

The EMFi element and the printed circuit board with the interface electronics areepoxy molded inside the aluminum cover. The function of the epoxy is toprevent the cover from bending when it is pressed, so that most of the force goes

Preamplifiers Comparators

reference generator

OutputsInputs

1nF

100M

10k

1M

EMFinput VREF OUT


to changing the thickness of the elastic EMFi and thus the charge generation ismaximized. The epoxy also acts as a hermetic seal for the EMFi element and theinterface electronics helping to avoid humidity based leakage problems.

Screentec was granted Finnish patent (FI 97477) for the EMFi keyboardtechnology in January 1997 and national patent applications to USA, Japan andmost European countries have been filed. The industrial sector for the EMFikeyboards is mainly consumer devices in public places, both indoors andoutdoors.

With conventional electronic circuits it is difficult to produce EMFi keyboards in highvolumes, because high quality operational amplifiers and large resistor values arerequired. These are expensive and require large PCBs and lots of components, so thatcosts of assembly and testing are also high.

The industrial sectors of the vandal proof keyboard is 30021650. The keyboard can beused in sectors 2320, 2411, 2960, 3002, 3220, 3230, 3310, 3320, 3330.

6. Description of the technical product improvements

The ASIC developed in this AE includes the basic function of the previousproduct: charge amplifiers and comparators for each key. New features offeredby the ASIC are the logic functions to convert the 16 individual key outputs into4 by 4 matrix output and the RS232 serial interface. The ASIC has all theelectronic circuitry required for 16 keys in one component. The block diagram ofthe ASIC is shown in figure


Figure 6. Block diagram of the ASIC

The analog signal processing block is the equivalent of the existing keyboardinterface. The charge amplifiers have been implemented using switched capacitortechnique. It makes possible to implement the long time constants needed usingthe small capacitors available in integrated circuits. It makes also possible toinclude automatic offset zeroing in the charge amplifier. This improves theperformance of the keyboard and guarantees a uniform switching behavior in allcircumstances. Schematic of one key input is shown in figure 7.

OU

TP

UT

BU

FF

ER

ANA1ANA2

ANA15ANA16

.

.

.

REF

SEL1 SEL2

OUT1OUT2

OUT15OUT16

.

.

.

TXD

VREF

ANGD

XTAL1 XTAL2

OSC

CLK

BIAS

IBIAS

Block Diagram of NAPPI / Juha-Matti Kujala 22.04.1997File: NAPPI:/doku/spec/kuvat/block04.ds4

DET

MA

TR

IXC

ON

VE

RS

ION

CO

NT

RO

LL

OG

IC

RS-232CONVERSION

LOGIC

CLKGEN

CLKS CLKL

DCTRL

ENSERIAL

TRENABLE

INP

UT

S -

CH

AR

GE

AM

PL

IFIE

RS

-C

OM

PA

RA

TO

RS

In

CrefAgnd


Figure 7. Principal schematic of the signal processing for one key

Support blocks generate voltages, currents and frequencies needed in other partsof the circuits. VREF block generates the analog ground voltage for the chargeamplifiers and comparators. BIAS block generates the bias currents for analogblocks. OSC block is an RC-oscillator. CLKGEN block generates non-overlapping clock signals for the switched capacitor circuitry.

The logic part of the circuit is divided into three functional blocks. CONTROLLOGIC determines the mode of operation for logic outputs. MATRIXCONVERSION converts the 16 key outputs into 4x4 matrix output. RS232CONVERSION sends the key data out in serial format.

OUTPUT BUFFER selects analog, digital or matrix converted key data to itsoutputs.

The analog part of the ASIC replaces 9 IC circuits, 42 resistors and 18capacitors. The logic part gives completely new functionality in the product. ThePCB size will decrease 60%, from 8x8cm to 5x4cm. Also the costs ofcomponents, assembly and testing decrease 40 - 50%.

The interface electronics will fit into a much smaller space allowing simpler andmore rigid mechanical structures for the EMFi keyboards. The reliability of theproducts will improve due to decreased amount of components on the PCBs.

7. Choices and rationale for the selected technologies, tools andmethodologies

There were three main reasons for considering improving the existing interfaceelectronics:

• production cost reduction• anticipated problems with DC offset in volume production• new functionality needs: serial and matrix coded digital outputs

Three possible technologies were found for improving the interface electronics.

Thick-film hybrid technology was a natural candidate, because Screentec wasalready familiar with it. In general the advantages of hybrid technology aresmaller size, higher reliability and possibility to do active trimming by adjustingthe passive components with laser during testing.

Very soon it turned out that the size reduction would be minimal compared tothe existing PCB with SMT components. The production cost was about the


same than for the PCB version. So the only benefit would have been thepossibility to trim away the DC offsets during hybrid production. Thedisadvantage was the NRE cost of 15 kECU.

The second alternative was the semi custom ASIC technology. Array basedASICs can offer the benefits of integrated circuits at significantly smaller NREcosts compared to full custom or standard cell solutions. Unfortunately there arevery few array circuits that can implement analog and logic functions on the samecircuit. Not a single candidate was found which could have integrated the 16analog input amplifiers with switched capacitor technique, which was requiredfor the automatic offset compensation.

The third alternative was Full Custom ASIC technology. A Full Custom MixedSignal ASIC could easily include all the interface electronics for the 16 keyelement and also the proposed additional functions. The first estimations showedabout 50% cost savings at annual production volumes of 20.000.

The existing circuitry could not be integrated as such because of high resistor andcapacitor values used. Switched capacitor technique can be used in ASIC circuitsto replace those, but it requires a complete redesign of the circuitry. Switchedcapacitor technique offers also a possibility to solve the offset problem byconstructing automatic offset compensation in the circuit.

The ASIC circuit in QFP44 package and a few external components can replacethe existing 8x8 cm PCB. The size reduction will be about 60%, which allowsmore flexibility in designing different mechanical constructions for the keyboards.The ASIC can also include the new functions, which could not have beenimplemented in the allowable space with hybrid or PCB technologies.

Though the ASIC alternative could meet the technical and economicrequirements, it seemed first impossible due to high design and NRE costs, highrisks and lack of ASIC knowledge. The design and prototype costs wereestimated to be about 100 kECU. Converting the conventional design into aswitched capacitor circuit included a risk, which could mean a second prototyperun and additional costs and delay.

The ASIC alternative was both a more demanding and more expensive choice todesign, but in large production quantities clearly the most economic choice. Thepayback time would be about two years, if everything would go as planned. TheASIC was the only possible way to fit the new functions in the space given andso it gave a clear added value to the product. The automatic offset compensationfacilitates mass production by removing the need for trimming.

Based on the facts above the full custom ASIC technology was chosen.


For design it was obvious that a subcontractor was needed for training andassistance in the design. There were three possible candidates close to Screentec

• Technical Research Center of Finland, Electronics laboratory• University of Oulu, Electronics laboratory• Fincitec Oy, an independent ASIC design house

Screentec chose Fincitec to be the subcontractor assisting in the design anddelivering the production components. Fincitec was selected because they were acommercial company, they had considerable experience about mixed signalASICs and they could also take care of the circuit production. They had an officevery close to Screentec, which was very useful for supporting Screentec’s work.

University of Oulu would have been a cheaper option, but the schedule and theASIC readiness for production would have been less predictable. TechnicalResearch Center would have technically been possible, but they don’t deal withthe production.

Fincitec quoted to Screentec separately the design phase and the productioncircuits. An agreement was signed between Screentec and Fincitec prior tostarting the project. The contents of the agreement are described in chapter 10,subcontractor information.

The AMS 1.2 µm CMOS process, being a mature and low cost technology wellsuited for mixed signal ASICs, was selected. Fincitec had experience of severalprevious designs using this process and numerous ready made cells. Because thecircuit is pad limited the line width has no effect on the circuit size.

The design was carried out together by Screentec and Fincitec. Screentec started thedesign work by purchasing PSPICE design system and creating the simulation modelfor the EMFi element. Screentec also simulated the charge amplifier structure used formeasuring the charge generated by the EMFi element. They built a prototype of thecharge amplifier, which was used to specify the requirements for the actual integratedcharge amplifier. Fincitec assisted Screentec in getting started with the simulator andgave hands on training in simulation.

Screentec chose PSPICE because it is a PC based low cost simulator well suited foranalog simulations. AMS provides simulation models for PSPICE, but they don’tofficially support it. So AMS doesn’t guarantee the simulation results.

Fincitec carried out the detailed analog design and simulated the operation in worstcase conditions. Fincitec used the ELDO simulator, which is officially supported byAMS. Screentec design engineer participated in the design and in the design reviews.

The logic functions of the chip were drafted by Screentec. They purchased XILINXFPGA design system for making the actual gate level logic design. The purpose was tomake a hardware model of the logic part of the ASIC. In this phase Screentec had


resource problems and it was agreed that Fincitec does the gate level design. Otherwisethe project would have been delayed by several months due to MPW schedules. TheFPGA prototype was not done because of lack of time. It was obvious that logicsimulations gave sufficient proof that the logic will work also in the application.Fincitec used Verilog-XL simulator for logic verification.

The layout design and verification were done by Fincitec with Cadence layout tools.The final simulations were done using the netlist extracted from the layout with theparasitic capacitance caused by the layout.

After each design phase the results were reviewed together by Screentec and Fincitec.We estimated the main risk to be in the accuracy and stability of the measurement ofthe small charge using the switch capacitor technique. Functionally the circuit is veryclear and the risk of having functional errors was small.

Prototype ICs were manufactured using Europractice MPW processing. Fincitectook care of obtaining the prototypes and communicating with the siliconprovider. Both Fincitec and Screentec tested the prototype ICs. Screentecassembled a series of product prototypes using the prototype ICs and testedthem thoroughly in all conditions. They worked completely on the first run.

8. Expertise and experience in microelectronics of the company and thestaff allocated to the project

Screentec has over 10 years of experience in manufacturing membrane keyboardsand related electronics and is known as a pioneer in this field in Finland. Ourkeyboard products are usually found in places where the conditions areespecially hard and demanding. The new keyboards based on EMFi technologywill meet even more demanding requirements than the standard membranekeyboards. Also in EMFi sensor technology Screentec has become the leadingmanufacturer of sensors and related electronics for various applications.Screentec has also experience in designing various electronic circuits, both analogand digital (including PLDs) and PCBs using both standard and surface mountcomponents.

Screentec did not have any prior experience in ASIC technology before the AE.Neither did we have experience of using CAE tools in the design.

9. Workplan and rationale

The workplan consisted of the following main tasks:


TASK DELIVERABLE RESPONS. WEEKSScr. Fin.

Project management Official reports Screentec 3ASIC specification Functional specification Screentec 3

Technical specification Fincitec 2Design softwarepracticing

Learning Screentec 1

ASIC design training Training Fincitec 1 1Digital design Logic circuit schematics and

simulation resultsScreentec 3

Logic conversion toASIC

ASIC logic circuit schematicsand simulation results

Fincitec 1

Analog IC design EMFi modeling and chargeamplifier simulation

Screentec 4

Analog circuit design andverification

Fincitec 5

Layout design IC-layout Fincitec 7Prototype ordering Order to Europractice Fincitec 0Test design Test specification Screentec 1 2Prototype IC manuf. 10 prototype ICs EuropracticeIC testing Tested prototype ICs Fincitec 1PCB design Product prototype PCB Screentec 2Assembly of productprototypes

Product prototypes Screentec 1

Testing of productprototypes

Tested product prototypes Screentec 6

Documentation Test document Screentec 3 1Dissemination Dissemination material Screentec 2

Total workload 30 20

The ASIC design phase took about 6 months. After that the prototype ICs wereordered using Europractice MPW. The manufacturing of the prototype ICs andtesting them took about 4 months. During this time Screentec designed the PCBand a test program for the product prototypes. The assembly and testing of theproduct prototypes took about 1 month, so the total time required for theexperiment was 12 months.

The project was delayed in the specification and design phases. The specificationdelay was caused partly by underestimating the time needed to get acquaintedwith the ASIC technology and partly by difficulties in a small company to freeresources for new development projects. The specification delay caused


difficulties at the design subcontractor, because the reserved resources had to becommitted to other projects.

These delays caused that the prototypes were made one MPW run, 3 months,later than planned. By speeding up testing the original schedule could be kept.The original and the actual schedules are shown in the following chart.

Planned (__) and actual (__) schedule

Task Nov96

Dec96

Jan97

Feb97

Mar97

Apr97

May97

June97

July97

Aug97

Sep97

Oct97

ASIC spec. _________Training ___ ____IC design __________ ____________Layout __________ ____________Test design ___ _____Document. _____ _____Prototypes ______________ _________________IC testing _____ ___PCB design __ __Assembly __Product test ______________

____Documents __ __

10. Subcontractor information

Subcontractor 1, Fincitec Oy

Fincitec Oy is an ASIC design house in Finland, who offers a broad range of servicesfrom FPGA to complex full custom ASIC circuits. Number of employees in Fincitec is40. Close to 200 circuits have been designed during 13 years of operation.

Fincitec offers services as follows:

Consultancy• technology selection• feasibility analysis• risk analysis• technical management

ASIC design• from FPGA to full Custom IC• analog, mixed and logic• from specification to testing

ASIC production• testing• packaging


• quality assurance• logistics• cost efficiency

Fincitec has a lot of experience in digital and analog ASICs. Fincitec’s specialtiesinclude:

• mixed analog/digital design• full custom design• micropower and low voltage design• EEPROM applications• RF design• up core integration

Fincitec is a vendor independent company. Their full set of ASIC design tools includesalso synthesis and automatic test pattern generator tools. Fincitec has a wide referencelist in the Finnish and European market.

Rationale for choosing / evaluation of the subcontractorScreentec does not have any prior experience in ASIC technology, so the designwas made together with a subcontractor. Screentec selected Fincitec not onlybecause of Fincitec’s long experience in mixed-signal ASIC design but alsobecause of Fincitec location close to Screentec, which makes co-operation a loteasier.

ContractThe main points in the agreement were:

• contents of the work• deliverables and delivery schedule• costs and payment conditions• responsibilities of the parties• project management procedures• change procedure• acceptance of the results• delay penalty• project termination• intellectual property rights• confidentiality

Subcontractor 2, Europractice

Europractice is a European Union initiative to improve the competitiveness ofEuropean industry by the adoption of advanced electronics technologies.


Europractice is open to industrial companies (especially SMEs), research institutesand academic users.

A complete service from idea to product by provision of:• Feasibility and proof of concept studies• Prototyping and low volume production• Access to large scale industrial manufacturing facilities• Custom design• Software• Training

Europractice can deliver low risk, low cost and easy access to the latest competitivetechnologies, specifically:

• IC Services (ASICs)• Multi-chip Modules (MCM)• Microsystems (MST/MEMS)

Europractice is run by several organizations. The MPW run used in this project wasorganized by Fraunhofer Institut für Integrierte Schaltungen (FhG-IIS)

Rationale for choosing / evaluation of the subcontractorEuropractice was selected because it offers MPW runs for several semiconductorprocesses.

11. Barriers perceived by the company in the first use of the AEtechnology

The main perceived barriers to access ASIC technology were:

1. Lack of ASIC knowledge2. High NRE costs of ASICs3. Fear for the risks of ASIC technology4. Special skills needed in design5. Design tools are expensive6. Difficult and expensive to make changes in ASIC


12. Steps taken to overcome the barriers and arrive at an improvedproduct

The following steps were taken to overcome the barriers.

1. Lack of ASIC knowledge Before this experiment Screentec didn’t have accurate knowledge on the technical

and economical possibilities of ASICs. It was not clear, how much could besaved and what technical improvements could be done. In the initialdiscussions and during the preparation of the FUSE proposal Screenteclearned about these things from the TTN.

2. High NRE costs of ASICs The design and prototyping costs of full custom ASICs are high, especially for

small companies. The calculated savings in production costs and theanticipated increase in production quantities showed such a short paybacktime that we could accept the NRE. The NRE was lowered by using MPWservice for the prototype processing. On the other hand, this increased thetotal cost if everything worked on the first prototypes.

3. Fear for the risks of ASIC technology ASIC technology seemed to have many risks, for example the following:

• unanticipated design problems• design errors• specification errors• unanticipated additional costs

These risks were discussed with the TTN and the subcontractor before theproject was started. Unanticipated design problems were ruled out by afeasibility study of the critical charge amplifier part of the circuit. Possibilityfor design errors was minimized by selecting an experienced subcontractor,who could take responsibility of their part of the work and who could alsoassist Screentec in our part of the design work. The risk for majorspecification errors was considered small due to simple functional structure ofthe ASIC. Minor errors could be easily corrected when the final productionversion is made after the MPW prototypes. Unanticipated costs wereprevented by careful planning of the project and a thorough subcontractingagreement.

4. Special skills needed in design It was obvious that we don’t have sufficient skills for ASIC design in Screentec.

When the project was planned and the FUSE proposal was prepared, wefound out, that there are many things in the design that we could do ourselves


after minor training. The more complex things like the switched capacitordesign and the ASIC layout we decided to subcontract.

5. Design tools are expensive A complete set of CAE tools needed in full custom design is far too expensive

for a small company. Even leasing the software for this design would havebeen expensive, and the UNIX based tools would have required lengthytraining. However, we could use low cost PC based design programs for thefunctional design of analog and logic parts of this small ASIC. The finalverifications were then performed by the subcontractor with their designsystems.

6. Difficult and expensive to make changesOnce an ASIC circuit is put into production, it is rather time consuming andexpensive to make even a small change. Thorough work in the specificationphase and careful design verification help in avoiding changes. Changes can bemade faster and cheaper, if they can be implemented by changing only themetal routing layers of the ASIC. In design this can be taken into account byadding unused components to the circuit and building resistors and capacitorsfrom smaller units which can be removed or added. Also using MPW servicefor producing the prototypes gave us an opportunity to implement changeswhen the production version of the circuit is done.

FUSE was of major importance in lowering the threshold of using ASICtechnology. The mental ASIC barrier was overcome by negotiations with TTN,by preparation of FUSE proposal and by ASIC training arranged by TTN.

13. Knowledge and experience acquired

In this project Screentec has gained the experience in the following areas:• Technical and cost benefits of using ASICs• ASIC project management• ASIC specification• FPGA and digital ASIC design• Use of analog design system PSPICE• Switched capacitor design basics

The ASIC experience gained enables us to specify an ASIC with sufficient care.By knowing how the design process is done we can better estimate the quality offorthcoming ASIC quotations. The models obtained in this project from Fincitecfor specification, design report and subcontracting agreement are very useful inthe next ASIC projects.


We found out that learning to use the PC based design systems was relativelystraightforward. The manuals and tutorials in the systems make self-learningpossible. There were not commercial training courses available for the designsystems when we needed, so we had to learn ourselves. Some assistance from thesubcontractor helped us from getting stuck in the problems.

Many of the above mentioned things are useful not only in ASIC projects but inall development projects in Screentec. The analog simulator was found out to besufficient for small scale ASIC design. It can also be used in conventional analogdesign to improve the design efficiency and quality.

14. Lessons learned

As a whole, the project went according to plans, and we didn’t have to learnanything the hard way. Some things that could be made better are discussedbelow.

The most visible problem was the delay in the first tasks of the project. In asmall company it is difficult to provide the design personnel sufficient time for adevelopment project. Any problems in the existing products disturb and delaythe development project. We can figure out two ways to overcome this problem.One solution could be to hire for the new development project a new person,who is not involved with the present products. This person could have previousexperience in the new technology and could thus ease the technology take-up.The other solution could be to subcontract a bigger part of the work.

A small company like Screentec is often hesitant to start marketing of a newproduct sufficiently early. We need to see that the product really works beforestarting the marketing. This means a slow ramp-up for the production anddelayed payback of the investment. The solution for this could be to increaseconfidence in the new technology and the development process by analysing therisks with external experts and making contingency plans.

Sufficient financing should be planned in the beginning of the project. Not onlythe product development need the money, but marketing and productionarrangements should be prepared for. In an ASIC project there are considerablecosts involved in taking the ASIC to mass production from the prototype phase.New masks are required if the prototype is made using MPW run. Theproduction test program has to be developed and the circuit has to becharacterized in order to validate the test program and the circuit operationacross different temperature, voltage and processing conditions. Cost for theseoperations can vary from 20 to 80 kECU.


A common learning for all these lessons is that good business, economical andproject planning will improve the chance of success and speed up market entrywith the new product.

15. Resulting product, its industrialisation and internal replication

At the end of the experiment we have a completely working prototype of the 16key keyboard realized with a full custom ASIC circuit. The next task is to makethe production version of the ASIC. The tasks include:

• preparing the production masks• preparing the production prototype lot• preparing the production test program and hardware• characterization of the production prototypes

The cost for the tasks above is about 50 kECU and the schedule is 6 months.The production version will be ready in the end of July 1999.

We have also to activate our EMFi marketing and we have already started co-operation with two companies located in Germany and Holland. Our financialsituation does not allow starting radical marketing activities just now. We arenegotiating of bringing new capital into the company for the investments requiredin expanding our EMFi business.

The EMFi keyboard business has started well with the smaller keyboards with 3, 4and 6 keys. These keyboards are made without the ASIC, because the ASIC is not yetin production, and it would be too expensive for these small keyboards. We areplanning to make a another version of the ASIC for these small applications.

The main application areas of EMFi-keyboards are:• Cash dispensers• Industrial data processing• Public places and outdoor use

- Public telephones- Elevators- Access control systems

• EX-environments- Oil industry- Chemical industry- Mines


We are also looking at other possible uses for the EMFi. All these applications havepotential for high volumes and they could need new ASIC circuits. At present thedevelopment is active in the following areas:

• Large area sensors for detecting human movements in houses• Non-contacting sensors for detecting breathing & heart beat of a person

lying in bed• Keyboard & switch applications• Sensors for measuring dynamic forces• Pickups for musical instruments• Microphones• Sound production

Applications that are already in production are keyboards for heavy use, impactsensors, pickups for musical instruments, patient monitoring sensors (detectingbreathing and heart beat in bed) and large area floor sensors for detecting humanmovements. Several other areas of applications have also been tested anddemonstrated. Development of new applications is carried out in confidential co-operation with customer companies, who want to utilize EMFi in their products.In order to protect the interests of those companies who have invested a lot oftheir efforts and money in applications development, EMFi is not generallyavailable for customers, except as customized sensor products developedtogether with the customer company.

Examples of EMFi sensor applications:

EMFi provides a cost effective solution for various different sensor applications:sensors with a small active area can be manufactured in high volumes by screenprinting the electrically conductive layers using thick film technology and sensorswith a large active area can be manufactured by laminating technology. Oneapplication area is patient monitoring. The EMFi sensor is placed under themattress and it is used for monitoring breathing movements and heart beat of a


person lying on the mattress. The high sensitivity of the sensor allows eveninfants to be monitored.

Picture 8. Patient monitoring.

Sensors for measurement of various dynamic forces have also been manufactured.The advantage of EMFi is that sensors of almost any size and shape can bemade. Even large areas can be covered by EMFi sensors easily and inexpensively,for example floors in applications were movements of people need to bemonitored.

Picture 9. Detecting human movements.

16. Economic impact and improvement in competitive position

Markets for vandal resistant keyboards in Europe are according to recent marketsurveys between 100 and 150 million ECU per year. The main users of vandalresistant keyboards are various manufacturers of automatic machines to publicand outdoor environments, these include banking cash and payment automates,ticket vending machines for railroads and subways, control units for elevators,code input devices and so on. The markets grow steadily because of theincreasing number of new applications.

EMFi technology has proved to have superior properties compared to othertechnologies in manufacturing keyboards for hostile environment. This, togetherwith the very positive response from the users of our EMFi keyboards, has


convinced us that it would be possible for us to gain within the next 3-5 years5% of the European markets, which at the moment are dominated by non-European companies. This would increase the turnover of EMFi based productsto the same level with the membrane keyboards. With the present electronicinterface it is, however, impossible to get the production volumes high enoughand the production costs low enough so that we could seriously enter themarkets. The table below shows the current and projected sales of Screentec’sstandard technology products and products using EMFi. Without theintroduction of the ASIC the sales of the Large EMFi keyboards would benegligible.

Screentec’s turnover by product category is projected in the following table.(million ECU)

Product 1998 1999 2000 2001Standard Technology 2.5 3.0 3.2 3.5Small EMFi keyboards 0.3 0.7 1.0 1.2Large EMFi keyboards 0 0.4 0.7 1.7

The biggest part of turnover comes from custom membrane keyboards.

The small EMFi keyboards sales include small systems with 3-6 keys, which canbe done profitably without the ASIC. This business has started to growpromisingly. This business we can reach without doing this FUSE project. Bymaking a reduced version of the ASIC we can further improve our profitability inthese products.

The large EMFi keyboards must use ASIC in order to be profitable. Without theASIC the sales of these larger keyboards will be negligible.

The production cost for the current electronic interface in large keyboards isabout 20 ECU if the production volume is in thousands. The component costsare about 15 ECU. The production cost will not drop significantly with increasedvolumes. The cost of the electronic interface is at present more than 50 % of thetotal production cost of the EMFi keyboard.

The production cost for the ASIC would be about 4 ECU for 5000 piecesproduction and about 2 ECU for 30 000 pieces production. This leads to 10ECU production cost of the electronics part when the production is around30.000. The saving is 50% compared to the present electronics and about 30%on the product level.

A typical competitor’s price for a 4 x 4 keyboard designed for heavy use is about75 - 100 ECU. With the present interface electronics we can sell our product for100 ECU. The introduction of the ASIC interface will enable us to lower the


cost of the electronic interface to a level which makes high volume productionwith a good yield possible and will give us a very competitive product.

Our estimation for the sales of the larger keyboards is presented in the followingtable.

1999 2000 2001 2002 2003 2004pieces (k units) 5 10 25 35 40 35unit price (ECU) 75,00 71,25 67,69 64,30 61,09 58,03sales (kECU) 375 713 1692 2251 2444 2031Profit (kECU) 56 106 253 338 367 305Cumulative profit (kECU) 56 163 417 755 1121 1426

The estimation assumes annual price erosion of 5%. The profit is estimated to beconstant 15%, because the production costs will decrease with increasingproduction volumes, which will compensate for the price erosion. The totalproduction volume will be 150 000 units and the total sales will be 9,5 MECU.

For the payback period calculation we have to take into account the costs fortaking the ASIC into production and the marketing costs. We can estimate thatthese costs are 100 kECU, which makes the total investment to 200 kECU. Fromthe table above we see that the payback period will be 26 months.

We estimate that the lifetime for this ASIC is 6 years, after which it is replaced withanother ASIC. Calculating the Return On Investment with 200 kECU investment and1426 kECU total profit will give average annual ROI of 39%.

17. Target audience for dissemination throughout Europe

Mixed signal ASICs have been found very useful in sensor interface applications. Thisproject could be very interesting for the applications as follows:

• keyboard and switch applications• sensors for measuring dynamic forces• large area sensors• non-contacting sensors

The industrial sectors which could benefit of this project are as follows:

Industrial sector Prodcom codeOffice machinery, computers 30Electronic components 321Communication equipment 322Sound & image 323Medical instruments 331


Instruments for measurement 332Industrial process control 333

Especially for the small size companies this AE could be useful. The maincriteria which will benefit the companies are as follows:

• The technology step from PCB to Mixed ASIC succeed excellentlywithin the schedule and the budget (well specified, well done)

• The Europractice services were used successfully for the MPWprototypes

• Activities and possibilities for the internal replication are high• High economic value and fast payback achievableApplication is interesting, easy to understand and easy to demonstrate

ELECTRONIC INTERFACE FOR EMF KEYBOARDS · 2001-09-12 · Application Experiment No 23597 30.12.1998...

Documents

Transcript of ELECTRONIC INTERFACE FOR EMF KEYBOARDS · 2001-09-12 · Application Experiment No 23597 30.12.1998...