[SI-LIST] Re: Simulating frequency dependent s-parameters in HSPICE
- From: Krishna Chaitanya <krishna1abc@xxxxxxxxx>
- To: "Sinha, Snehamay" <snehamay@xxxxxx>, ray.anderson@xxxxxxxxxx
- Date: Mon, 12 Mar 2012 16:50:14 -0700
Thanks Snehamay, Ray and all others for helping me understand how
s-parameters are simulated in HSPICE.
Thanks for the set of guidelines Ray. I think Q3D has the adaptive sweep.
One quick question regarding the frequency range for s-parameter extraction
using Q3D. When you say the highest frequency of interest, should I
consider maximum data rate I am targeting or the bandwidth from the
rise/fall time?
If I am looking for a 20 Gbps with rise/fall times of 10ps, should I
consider the frequency sweep from DC to 100GHz (corresponding to 10ps
rise/fall) or to 10 GHz (corresponding to 20Gbps)?
I am planning to use adaptive sweep so that the step size can be determined
by the solver as mentioned earlier.
Thanks,
Krishna
On Mon, Mar 12, 2012 at 4:32 PM, Sinha, Snehamay <snehamay@xxxxxx> wrote:
> **
> Krishna,
> The S-parameter models will have S11, S21, ...etc data at multiple
> frequency points. When you run a simulation with S-paramater models in
> HSPICE, the frequency domain data is first converted in time domain data
> (Fourier transforms) and then convolution is used to calculate the nodal
> voltage and currents.
> So all the frequency dependence in the model is comprehended by HSPICE.
>
> regards,
> Snehamay
>
>
> ------------------------------
> *From:* Krishna Chaitanya [mailto:krishna1abc@xxxxxxxxx]
> *Sent:* Monday, March 12, 2012 4:42 PM
> *To:* Ihsan Erdin; Sinha, Snehamay
> *Cc:* si-list@xxxxxxxxxxxxx
> *Subject:* Re: [SI-LIST] Simulating frequency dependent s-parameters in
> HSPICE
>
> Hi Snehamay, Ihsan and others,
>
> Thank you very much for the SPICE syntax. I used that for the
> simulations but not clear how it guarantee frequency dependent RLGC are
> taken into account.
> When I give a PRBS input corresponding to a bit rate of say 2GBPS (or 1
> GHz of clk), does it mean the HSPICE will pick the RLGC values
> corresponding to this particular frequency of 1GHz?
> I do not see any visible connection which tells the SPICE to pick the RLGC
> values corresponding to the input data rate.
> Can you please help me understand what is happening when I simulate using
> s-parameters in HSPICE
>
>
> On Mon, Mar 12, 2012 at 9:55 AM, Krishna Chaitanya
> <krishna1abc@xxxxxxxxx>wrote:
>
>> Thanks all. I have few questions.
>>
>> I did try using s-element and I am not clear how to interpret my
>> simulation results.
>> For a simple case of inverter based driver and receiver,
>>
>> INV (driver) -> Through Silicon Via (Interconnect) -> Inv (Receiver)
>>
>> I have the s-parameter touchstone file for a range of frequencies for
>> TSV extracted using Q3D extractor. I simulated this in HSPICE using
>> s-element and I got some eye diagram for a PRBS pattern for a particular
>> input data rate.
>>
>> From my understanding, the R and L values atleast change with frequency
>> and depending on that my eye opening should change.
>> If I use the s-element method, I get a single eye diagram. How should I
>> interpret it?
>> Does it mean the eye diagram which I get after simulating using s-element
>> includes the effect of all the frequencies on RLGC parasitics?
>>
>> In short I am not clear how s-element simulations guarantee that my
>> simulation results include frequency dependent RLGC parasitics.
>>
>> Thanks,
>> krishna
>>
>>
>> On Mon, Mar 12, 2012 at 9:29 AM, Ihsan Erdin <erdinih@xxxxxxxxx> wrote:
>>
>>> Krishna,
>>>
>>> In hspice, you can directly plug in those s-parameters to your netlist
>>> as an s-element. As there's no need for a w-element using one wouldn't be
>>> right either. You can model the rest of the tracks with the w-element.
>>> Below, I suspect you're referring to a totally different case which is
>>> about assigning freq. dependent PUL parameters to the w-element from a
>>> touchstone file. This can only be be used when the track parameters are
>>> computed with a third party tool and completely irrelevant to what you're
>>> trying to accomplish in this particular situation -if I understood your
>>> case correctly, of course...
>>>
>>> Regards,
>>>
>>> Ihsan
>>>
>>> On Mon, Mar 12, 2012 at 11:28 AM, Krishna Chaitanya <
>>> krishna1abc@xxxxxxxxx> wrote:
>>>
>>>> Hello All,
>>>> I am trying to analyze the impact of frequency dependent parasitics of
>>>> Through Silicon Vias on data rate. I used Ansoft Q3D extract to obtain
>>>> RLGC
>>>> parasitics as s-parameter Touchstone file for a range of frequencies.
>>>> Now I
>>>> would like to know how can I use this file in HSPICE simulation. When I
>>>> use
>>>> w-element method in HSPICE it can take touchstone file as input but I am
>>>> not sure whether it is the correct way to simulate any frequency
>>>> dependent
>>>> parasitics in HSPICE.
>>>>
>>>> Any help?
>>>>
>>>> Thanks,
>>>> Krishna
>>>>
>>>>
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>>>
>>>
>>> --
>>> Ihsan Erdin
>>>
>>>
>>
>
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