CSS Mixed Signal ASIC Solutions

From Concept through Production,
your Mixed Signal ASIC Solution.


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.