CSS Mixed Signal ASIC Solutions

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Custom Silicon Solutions (CSS) has just released SPICE simulation models for our CSS555 and CSS555C ICs.  These models provide a simulation capability at the component level.  To make them portable across many simulators, only Level 1 device models are used.  The voltage comparators are modeled with BLM gain blocks to reduce simulation time.  Even with these simplifications, the model provides a very good representation of the real IC.


The CSS 555 Timer model includes:

   1) Supply Current (over VDD)

2) Input Switch Levels

3) Propagation Delay Time

4) Output Drive (over temperature and VDD)

5) ESD Clamp Diodes and Pad Capacitance

The power and trip level settings (stored in EEPROM) change the IC’s supply current, propagation delay and trip level parameters.  Separate SPICE model files are provided for each combination of power and trip level settings.

CSS 555 SPICE Model

The CSS555 SPICE model has been structured to provide an accurate model that runs quickly and is compatible with most SPICE simulators.  It includes the analog portion of the IC and covers most of the important electrical characteristics, including supply current, input levels, output drive and propagation delay.  The model can be used over a wide operating range: VDD = 1.2V to 5.5V, Temperature = -40°C to 85°C.  Most of the device parameters are valid across this range.  Models for different configuration settings (power & trip levels) are also provided, along with tables to adjust the models for worst-case conditions.  Complete details are provided in Application Note 555-2 “CSS555 SPICE Model”.


CSS became ISO 9001: 2008 certified on July 1, 2009. We have been working over the past year to achieve this important milestone.  Everyone at CSS worked hard to make it happen.  I think we all believe that the systems that are now in place will help us to better serve our customers.  We have also found that the sytems make our job a little easier – by formally putting in place the necessary processes to get the job done.

Robert Shackelford, CSS Quality Manager, was the key person at CSS working to accomplish this goal.  Robert is shown below with Derek Luffman, Certified Lead Auditor, with IMSM, on July 1, 2009, following our successful audit.

Derek Congratulates Robert

Derek Congratulates Robert