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Simulators >> Circuit Simulators >> CAN HSPICE do the design of 1 Ghz ADC .?
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Message started by manisms on Dec 27^th, 2006, 9:04pm

Title: CAN HSPICE do the design of 1 Ghz ADC .?
Post by manisms on Dec 27^th, 2006, 9:04pm

hi
i want to design the 1GHz 6bit ADC in TSMC 180nm RF PDK. using the HSPICE simulator.
my question=> if i use TSMC 180nm RF hspice.and if i include this file into my HSPICE simulator and start the design of that ADC '> can i design this way correctly.???
because i am having the HSPICE simulator which is not the rf simulator.
so by adding the RF model file would i be able to design the circuit correctly.
if the answer is no then my assumption is that in the 1Ghz adc i dont need to run the s parameter analysis or pss or pxf analysis.
so i can do the design by usign the Hspice .
plz revert back..
regards

Title: Re: CAN HSPICE do the design of 1 Ghz ADC .?
Post by makelo on Dec 30^th, 2006, 2:27pm

It sounds to me like there are two questions: Will the TSMC 0.18RF PDK work to design a 1GHz ADC? Second, will HSPICE work with the RF PDK?

As to the first... The RF PDK was likely built from measurment data taken in the 500MHz to 20GHz range so that is the frequency range where the transistors will be most accurately modelled. There may also be models good down to DC depending on the kit. In either case, it should work but the bias may be slightly off if the low frequency behavior is not well modelled.

The second question is really a matter of whether or not the RF PDK will work in HSPICE. This will take some reading of the manuals and further investigation to see if the formats are compatible.

-Makelo

Title: Re: CAN HSPICE do the design of 1 Ghz ADC .?
Post by simon2 on Sep 20^th, 2007, 4:57pm

Hi manisms,
you probably know this by now, but I contribute it for the benefit of others reading this "after the fact":

The PDK should contain a file or group of files with the extension .l or .lib (maybe .txt) - open them with wordpad or notepad and yhou will see that they are in fact Hspice library files - Hspice will use them directly (so will spectre, eldo, winspice, pspice and quite a few others).

I have done ASIC RF design to 5GHz using both Hspice and Spectre. My comment would be: You do not need the "RF" versions; it is simply a matter of understanding the models, their parasitics and their coverage, correctly. That said, if you do not understand (or feel that you dont understand) the models correctly, or do not have the mathematical skills and knowledge to apply the available models to "RF" problems, then it may be a good idea to pursuade your boss to spend the money on those "RF" tools to build confidence with the results of your simulations and of your design. They are basically encapsulations of expertise, which you can apply. In themselves they do not guarantee success, you still need to be able to critically decide if they are telling you the truth.

To help you decide if you can do your design in a common or garden variety of spice, or if you need a "bundled" solution, take a look at one of the resistor models in your PDK - do you know sufficient to be able to generate the schematics, bind the libraries then run the simulations in spectre, or write the scripts for Hspice to run a "Resistance vs Temp" simulation, or an input impedance plot to 10GHz or a CV curve for one of these resistors?

If so, then the answer is yes you can do RF simulation in either tool.

Just as an anecdote: I know of at least one person who has used Excel not only to do the circuit simulation, but a parameterised layout as well. So the answer is probably that all of these tools simply solve the matrix you pose them. The real skill is in how you pose the question in the first place.

Cheers,
SimonH.