CSS Mixed Signal ASIC Solutions

From Concept through Production,
your Mixed Signal ASIC Solution.

Nuts and Volts

The CSS555 low-power programmable version of the 555 family of timer ICs. It operates at a current under 5 µA and a supply voltage from 5.5V down to 1.2V. These qualities make it particularly well-suited for long lasting battery and small solar powered projects. It can be used in standard 555 configurations as supplied, but it is also user programmable to produce extended timing periods.

Author James Senft (a.k.a. TinkerJim) wrote an impressive 4-page article in the February 2016 edition of Nuts and Volts magazine. He featured some of the practical benefits and applications of the CSS555 illustrated by a few of his  projects.  The website  www.instructables.com has further descriptions of two of these applications.

Jim has shared another project he made with the CSS555 (posted below); the Tinker Trolley.
Every winter season, it makes its rounds beneath the Christmas tree, its schedule being set by a CSS555 in astable mode with a long delay and a short run.  It shuts down operations at night.

Share your CSS555 timer project with a post.

If you have used one of TinkerJim’s instructables let us know how it turned out.

Another Application of the CSS555

James Senft

In its extended or programed mode, the CSS555 is capable of very long period astable operation with a low duty cycle.  This capability was used to make the operation of this model streetcar, now christened as the “Tinker Trolley”,  much more interesting.

The little battery powered trolley was made over two decades ago to run around tracks set up beneath the Christmas tree (and as far beyond the region of the tree as the domestic authorities would allow the tracks to extend pending delicate negotiations each Advent).  Originally, the streetcar had an ordinary toggle switch poking out of the roof to turn it on for its endless rail rattling runs.  But then later,  someone would have to go over to catch it to turn it off for a rest for the batteries – and for the ears.  Eventually, tiring of these manual switching chores, the poor car often ended up just setting idle for long periods, even days sometimes.  When the CSS555 became available, a perfect application for it was waiting!  Thecircuit shown on page 18 of the “CSS555(C) Applications Circuits” document was cobbled up on a piece of strip board, mounted on the underside of the roof as shown in one of the photos, and the toggle switch replaced by a phototransistor.  The circuit used timing components to give a period of approximately 3 min. with an on time of about 12 sec.  (RA = 4M7, RB = 100K, RF = 100K, CT = .01µF, and multiplier M = 10K ).   Now the trolley starts itself up, runs around its track layout once or twice, and then parks itself for a nice quiet interval, repeating this cycle all day long.  This is a very satisfying operating regime for the trolley!

When at rest, the circuit draws only 6 µA.   In addition, the Reset pin is connected to source VDD through the phototransistor and to ground through a 1Meg resistor.  This arrangement puts the trolley to sleep at night and starts it on its rounds every morning.  The streetcar thus operates autonomously for about five days on a pair of rechargeable AAA batteries.  Just for variety, maybe next Advent, we might alter the operating schedule by reprogramming the CSS555, just changing the multiplier from M = 10K  to M = 100K .  Then Tinker Trolley would run for about two minutes every half hour !

Tinker Trolley Inside T T

CSS successfully completed an annual audit for ISO 9001:2008 on July 9. 2014.  Pictured above on the left is Keith Shelton, CSS Quality Manager, with the auditor, Richard Cornick, from QAS International.  These annual audits are to assure that CSS is performing to the requirements of ISO: 9001:2008, but they are also an opportunity to discover new ways to enhance our performance to the ISO 9001 standard.  CSS is pleased to act on these  new “suggested improvements” to improve our Quality System.

This begins our 6th year using our Quality Management System (QMS) that was established in 2009 with the assistance of “International Management Systems Marketing Limited” (IMSM).  IMSM typically assists small companies, like CSS, to establish a QMS that fits their needs.

We feel that our Quality Management System is necessary to maintaining quality in all we do – the design, production and delivery of custom mixed-signal ASICs.  The ISO 9001 Procedures, Forms and Work Instructions all work together by providing the framework for our work at CSS.


The Engineers of CSS – Allan Stewart

November 11th, 2014 by Keith
The Engineers of CSS – Allan Stewart

CSS has a great staff of engineers, but since they are often working “behind the scenes” they may not be well known outside the Company. This Blog, featuring Allan Stewart, is a continuation in the series of interviews titled “The Engineers of CSS” which will hopefully help everyone to know them much better.


Allan Stewart

Here is a little bit about Allan in his own words.

I graduated with a BSEE  for the University of Strathclyde, Glasgow Scotland in 1975 and began working as a circuit design engineer for Telecommunications, Defense, and Medical companies in the UK.  I joined Burroughs/Unisys in 1984 to work on circuit board development, and transferred to Orange County to take up a circuit design manager position in1987.  I joined Adaptec in 1996 responsible for Disk Drive servo controller ASIC development, and moved on to TI Storage Products where I also became involved in Disk Drive Read channel development.  I joined Calimetrics as Director of ASIC development in 2000 – working on multi-level CD and DVD technology development storage products.  I became an independent consultant in 2003 working on a number of projects developed jointly by Treehouse Design in Colorado and Chronicle Technology in Irvine.  I began working exclusively for Chronicle starting 2011, initially developing a 1.5Gbs SerDes interface for High Speed Video applications, and latterly worked on the 65nm and 28nm Bitcoin devices for Butterfly Labs.


CSS: You have a very impressive background as indicated in your history as provide above. What were the most interesting or technically challenging projects you have worked on during your career?

Allan:  From a technically challenging perspective I did a 1.5 – 2.5 Gbit/s SerDes with Chronicle just prior to the 65nm bitcoin chip, which was quite challenging. It combined high frequency PLL work along with some high speed digital requirements, allowing me to re-visit some of my old circuit board design challenges from earlier in my career.

CSS: You started working at Chronicle Technologies prior to the merger of Chronicle and CSS in 2013. What do you feel have been the advantages of the merger?

Allan:  I think the benefits were the result of each group having different strengths in terms of the depth of their capability.  Chronicle had more depth in design and layout, CSS brought the production test capability and ISO certification.  The result was not a significant overlap in skills and a good combination of the skills for ASIC design, test and manufacturing.

CSS: I know that you were a key person in the recent development of the bitcoin chips. Both the 65 nm and the 28 nm chips were successful complex digital designs. The 28 nm chip was an especially large ASIC, with 5.5 billion transistors!   What do you remember most about these developments?

Allan:  The 65nm was probably the more difficult of the two designs.  We had to figure out the architecture – we experimented with 5 or 6 different technologies trying to get the combination of speed and power we desired.

The test development was a challenge also – this was really the first time CSS and Chronicle had worked closely together – so it was a learning experience – but in the end I think a very successful one.

From a design perspective, the 28nm was more straightforward. We identified & designed the cells that needed to be improved to meet our new targets.  However. since this chip increased the number of Hash Engines from 16 (on the 65nM design) to 1024, it was huge and consumed 350Watts power.  These were the challenges.

Test results were excellent. Power was significantly lower and the operating frequency significantly higher than projected. We spent a lot of time estimating parasitic effects and these results were now showing it had been time well spent.

CSS:  Do you have any spare time for hobbies or other activities outside of work?

Allan:  Soccer is my main pastime, although I enjoy baseball in the soccer off-season. My preference would be to be still playing soccer, but a combination of injuries and the passing of time means I have to content myself with just watching now.


Nanium Develops Advanced Package for CSS

November 11th, 2014 by Keith

Nanium S. A. recently published a Press Release regarding an advance package they developed for CSS:

“Nanium S.A. has unveiled what the company believes is the industry”s largest Wafer-Level Chip Scale Package (WLCSP), a 25x23mm packaging solution produced in volume on 300mm wafers.  Entirely developed in-house for Custom Silicon Solutions (CSS), a California-based provider of complex mixed-signal ASIC solutions, the customized Fan-In Wafer-Level Packaging/ WLCSP solution is nine times larger in area than the industry standard WLCSPs, typically measuring up to 8x8mm.


The Nanium Chip Scale Package Developed for CSS

“After completing a very successful high volume run of a 65nm product in eWLB at NANIUM, we approached them with our next 28nm WLCSP requirements. The first article worked as promised and enabled CSS to get to market quickly with an ASIC unprecedented in thermal and computational performance”, said Mike McDaid, Director of Sales at CSS in a statement.

“No other package solution in existence would have achieved the low lead resistance and high reliability we demanded. This ASIC in Nanium’s WLCSP establishes a new world class of integration, beyond VLSI-SOC (Very Large Scale Integration System-on-Chip). The final product is just about the maximum reticle size allowed and consumes hundreds of Watts!” McDaid added.

The wafers with the high-performance digital chips are produced with 28nm CMOS technology and contain over 5.5 billion transistors, one of the largest transistor-count chip produced by Global Foundries. Once produced in Dresden, Germany, wafers are sent to Nanium for packaging.

The WLCSP solution developed by NANIUM relies on a high count of 1,188 solder balls at a wide BGA pitch of 0.7mm. It has successfully passed more than 400 temperature cycles on board.

Low power consumption is of paramount importance in scenarios where uninterrupted use is required for maximum efficacy and minimum inconvenience as in medical devices, wearable or portable electronic products and internet-of-things (IoT) devices. Replacement of a battery in mid-use of a therapy session or data-acquisition period, for example, is not an option in such devices.

CSS has developed key design techniques incorporated within an application specific integrated circuit (ASIC), that enable us to maximize the use of battery charge by increasing the efficiency of the power delivery mechanism which is crucial to such devices. These devices typically require a switch-mode regulator such as a step-up or Boost/Flyback converter or step-down/Buck regulator. Step-up converters are used so that higher voltages than the battery can be attained for the operation of certain modes (neuro-stimulation, sensor operation, etc.). Step-down or Buck converters that provide voltages lower than that of the battery may be used to optimize the power consumption of the device. This is because many circuits only rely on the supply of a certain amount of current as long as the voltage itself is above a certain value.   Using a linear or LDO regulator to create the lower voltage does not lower the power consumption as it only results in power loss across the regulator itself. For example, given a 3.6V battery that supplies 200 uA and a linear regulator output of 1.2V (to power circuits that can operate off 1.2V) means that the battery provides 720uW of power of which 480 uW is dissipated across the linear regulator. With only 240 uW finally delivered to the circuits, the linear regulator approach at best achieves an efficiency of 33%. A switch-mode regulator such as a Buck converter may hence offer a more efficient implementation. However, both step-up and step-down converters can themselves consume a large percentage of the energy budget, especially in applications where supply current usage is below 100 uA.

By using novel circuit techniques within the ASIC, power that is usually wasted in the voltage conversion process can actually be re-harnessed to sufficiently offset the operational current of the converters themselves. This is very important in low-current applications, since without such techniques, converter efficiency is usually very poor at low load currents as shown in the graph below for a Buck-converter. Devices that operate with currents below 20 uA have been successfully implemented using these techniques, thereby making them ideal for medical devices, wearable/portable electronics and the IoT arena.




An Advanced Bitcoin Mining Chip

August 10th, 2014 by Keith

CSS is now in production with the world’s most advanced Bitcoin mining ASIC. Implemented in 28nm, it contains over 5.5 billion transistors – the largest transistor count ASIC ever produced at Global Foundries.

A Slice of the SHA-2 Core, Implemented for Bitcoin Mining Purposes

A Slice of the SHA-2 Core, Implemented for Bitcoin Mining Purposes

In addition, by utilizing proprietary circuit designs developed by CSS, our Bitcoin mining ASIC achieves industry-leading power efficiency and engine density.

• 3x more power efficient than the nearest competition’s 28nm Bitcoin chip
• 2x more efficient than the only competitor using 20nm technology!

This chip is the second generation of a similar version produced by CSS last year. That version contained 16 Hashing engines and was implemented in 65 nanometer technology.

If you are interested in a full custom chip, please send an inquiry.  We will be happy to answer your questions and provide a no obligation quote for the full service development and production of a custom ASIC to meet your needs.


The Engineers of CSS – Curt Dodds

August 10th, 2014 by Keith

The Engineers of CSS – Curt Dodds

CSS has a great staff of engineers, but since they are often working “behind the scenes” they may not be well known outside the company. This article, featuring Curt Dodds, is a continuation in the series of interviews titled “The Engineers of CSS” which will hopefully help everyone to know them much better.

Curt Dodds - CSS Test Engineer

Curt Dodds – CSS Test Engineer

A little about Curt in his own words:

In 1966 while working for McDonnell Douglas, I applied for a 4 year, state sponsored, apprenticeship program to become a “Journeyman Electronics Technician”. Luckily I was accepted.

For those 4 years I attended evening college classes and every 3 months I was moved to a different electronics department. I got to experience every phase of the electronics operations like fabricating cables encapsulating modules, engineering design, circuit fabrication, testing, failure analysis etc. At the end of those 4 years I was totally hooked by electronics. My garage became a laboratory where I constructed circuits of all varieties, even making my own printed circuit boards.

I had NASA certification for most phases of construction for space electronics. For 3 more years I ran a thick film fabrication lab, building ceramic substrate circuits for space vehicles.

In 1973 the company began moving their operations to St. Louis Mo. Not wanting to move, I applied to Hughes Aircraft for a job. I was hired into their infant electronic watch program. There I discovered the world of microprocessors and micro-controllers. After learning to program those in assembly language, I designed, built and programmed testers used for production of the watches. Moving from LED to LCD displays, our finally was the calculator watch. After that, world competition forced Hughes out of the watch business.

I transferred into the micro-electronic design and analysis lab where I learned to program in BASIC then C languages, continuing to design and build programmable test systems for analyzing and characterizing each new CMOS IC the company produced.

Raytheon purchased the company and decide to close the Newport Beach plant in 1999. Not wanting to commute to near LAX, I was very excited when offered a position with CSS. I gladly accepted and have enjoyed the challenges presented here since.


CSS: When CSS and Chronicle Technology merged, the engineering staff increased significantly and we are designing a wider variety of custom ASIC’s. We are also expanding our testing facilities and equipment to meet the increased volume and variety of products. Do you feel our present approach of custom test program development will serve us well in this new

Curt: Our current test systems are tried and proven – very stable and versatile. However,
our rapid growth will require more testing capabilities soon. I am currently investigating several approaches for designing a new test system. I want to make sure our new a hardware platform that will serve us for many years to come.

CSS: In addition to test program development, you also assist CSS with our computer system organization. I understand you also do a lot of computer “work” at home as a hobby. Can you tell us something about your computer hobby at home?

Curt: I have 5 desktops, 2 laptops, and 2 tablets. Typically 3 or more are running each evening.
I am obsessed with Linux distributions; with an occasional BSD release thrown in. My busiest desktop has 49 distributions, plus XP and win 7. I tend to cycle through them sequentially, a different operating system each time I power up, or reboot.  Distrowatch.com is my daily pulse on what is going on in the Linux world.
So far I have not felt the need to buy a 64-bit computer. I also have a couple of Raspberry PIs, an arduino-uno, and various other toys. I’m currently learning how to use QT-creator (an IDE) for C programming on the PI, and using Eclipse for C, on a TI MSP430 Launchpad, a micro-controller development board.

I’m also the computer nerd that family and friends turn to when they have problems.
So, I never seem to run out of things to do at home.

CSS Completes ISO 9001:2000 Audit

CSS Completes ISO 9001:2000 Audit

CSS successfully completed an annual audit for ISO 9001:2008 on July 9, 2014.  Pictured above on the left is Keith Shelton, CSS Quality Manager, with the auditor, Richard Cornick, from QAS Interna8tional.  These annual audits are to assure the CSS is performing to the requirements of ISO: 9001:2008, but they are  also an opportunity to discover ways to improve beyond the basic ISO requirements.   CSS is pleased to act on these “Suggested Improvements” to further enhance our Quality System.

This begins our 5th year using our Quality Management System (QMS) that was established in 2009 with the assistance of “International Management Systems Marketing Limited” (IMSM).  IMSM typically assists small companies, like CSS, to establish a QMS that fits their needs.

We feel that the CSS Quality  System is necessary to maintaining quality in all we do – the design, production and delivery of custom mixed-signal ASICs.  The ISO 9001 Procedures, Forms and Work Instructions all work together by providing the framework for our work at CSS.


The Engineers of CSS – Frank Bohac

June 1st, 2014 by Keith

CSS has a great staff of engineers, but since they are often working “behind the scenes” they may not be well known outside the company.  This article, featuring Frank Bohac, is the third in a series of interviews titled “The Engineers of CSS” which will hopefully help everyone to know them much better.  A little about Frank in his own words:

I’ve always enjoyed science, but when I took my first course in electronics in high school, I knew I wanted a career in electronics. While in high school, I worked part-time in a TV repair shop where I gained a lot of practical experience troubleshooting audio and video equipment.  I got my BSEE and MSEE from Purdue University, with an emphasis in circuit design and solid-state physics. As part of my master’s program, I worked as a research assistant, applying thermal infrared imaging to the fields of biometrics and remote sensing.

After completing my studies at Purdue, I joined the R&D group at Hughes Aircraft in Newport Beach, where I worked on Charge Coupled Devices (CCDs) for several years and then switched to EEPROMs (a brand new field at the time).  After helping to develop the EEPROM technology into a practical nonvolatile memory, I joined the microelectronics group, designing mixed-signal ASICs, mostly for industrial and automotive applications.  During my tenure at Hughes (~ 20 years) I designed about 40 integrated circuits and was issued ten patents.

In 1997, Keith Shelton and I left Hughes (then Raytheon) to start CSS. Over the past 15+ years, we have produced a wide variety of mixed-signal ASICs for commercial, industrial, medical and military applications.

Frank BohacFrank Bohac


CSS:  You were a founder of CSS and have been designing mixed-signal circuits here and before at Hughes Microelectronics for many years. What has been the most interesting or challenging designs you have worked on?

Frank:  I have especially enjoyed the projects requiring ultra low voltage and low current requirements, mostly used for medical applications. (i.e. cochlear implants & bio-metric monitors) The challenge of getting the most functionality for each micro-watt of power has always been an interesting aspect of battery-powered circuits.

CSS:  When we merged with Chronicle a lot of engineering talent was added and we have added even more since then. Besides providing CSS more design resources, what do you feel are the advantages of a larger design group?

Frank:  I think the merger of Chronicle and CSS has added significantly to the range of products and technologies that we can address. Each member of our technical staff brings a different set of skills and experience, so new challenges can be viewed from different perspectives. This means we find better solutions to the wide variety of requirements found in today’s advanced ASIC’s.

CSS:  I know you are very busy at work, but hopefully you have some personal time. Do you have a hobby or other personal activity you can tell us about?

Frank: I’m an avid bicycler – it helps me clear my mind and stay active.  I also enjoy woodworking and gardening.



CSS555 to Custom ASIC

June 1st, 2014 by Keith

The CSS555 is a very low power timer IC (active current < 5 micro-amps).  It also has a programmable internal timing capacitor and a divider on the output which can be programmed to divide the output pulse in decades from 1 to a million.  However, it was the very low power that attracted Epitel to the device.  They wanted to use it in a medical application to study epilepsy – a battery powered sensor and data transmitter.  Their first application used the CSS555 in a small custom package.  This worked well, so they decided to build a custom ASIC with additional capabilities based on the CSS555 low power technology – the CSS094.

The CSS094 combines a low power 555 Timer with a 6-channel amplifier.  It can be used to monitor up to 6 biometric parameters.  The 555 circuit generates timing control clocks and a FM signal for the antenna.  A high voltage driver has also been included to drive the antenna directly.  An internal EEPROM provides storage for a serial number, calibration and configuration data.  The low power specifications are impressive: 10 micro-amps operating current with less than 50 nano-amps in the sleep mode.

2ch-transmittrThe Epoch Transmitter

The resulting product from Epitel, the “epoch system” provides wireless in vivo recording for low-cost, long-term monitoring.  Depending on the battery, the epoch transmitter (using the CSS094) can provide 2 months to 6 months of continuous monitoring.   See the Transmitter Implant page on the Epitel webpage for more complete transmitter specifications.

Low power instrumentation ASICs are a specialty of CSS in our custom ASIC designs.  We often combine this capability with our non-volatile memory latch technology to provide programming capability, as we did with the CSS094.  If you have an application needing very low power in a mixed-signal technology (combined analog and digital), please call us at 949-797-9220 or use our contact form  for a no obligation recommendation.

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