# Is a circuit simulation package available with models from multiple vendors?

I need to simulate a filter that will be used with a DAC. I need to model noise, accuracy, and drift to calculate ENOB and identify tradeoffs. I have used LTSpice for my modeling needs for the last 10 years. My company is willing to buy a more advanced tool for me to use, but I have no experience creating my own models. Most of the models available from Analog Devices and Texas Instruments are for their own SPICE programs (LTSpice and TINA-TI). Is there a popular SPICE package on the market that includes lots of parts models from multiple vendors?

• The spice packages can never "catch up" and be up to date with all the latest and greatest ICs and models. At work I have Pspice and I almost never use it. I prefer LTspice instead. – Mike Mar 26 at 22:07

You won't find a spice package that does what you want. Manufacturers don't have models that they give out other than the spice models that they already have, because there is a potential IP loss (a spice file that was not an approximation could easily be used to generate a circuit in silicon). Most of these models are not precision models, and only simulate basic functionality.

A good substitute is to use b-sources which have rounding to simulate digital systems.

V = floor(V(bits)/2^16)*5


I've actually simulated systems with noise and other errors in this manner (its and equation so you can generate any kind of error and the systems had DAC's and ADC's (an MPPT solar controller). Lt spice also has noise sources that can generate error. In this manner, one can get as complex as they want.

In my experience, ENOB and noise level of detail is not always needed as it takes time to approximate a digital device. But if you had to, you could get very detailed with only a datasheet and LT spice and a little know how.

• Thank you. What are "b-sources?" Googling didn't help me. FWIW, I do not need to simulate the DAC, just the analog filter. – justinis Mar 26 at 23:24
• I found the answer to my question. "B-sources" are behavioral sources: ltwiki.org/?title=B_sources_%28complete_reference%29 – justinis Mar 28 at 0:10