[sdiy] Any SSM2164 pspice model available on the net ??

Tom Wiltshire tom at electricdruid.net
Wed Mar 19 18:13:40 CET 2014


Understood. You can comment it out if you want. I've certainly never seen any sim where it had an effect.

T.

On 19 Mar 2014, at 15:56, Neil Johnson <neil.johnson71 at gmail.com> wrote:

> Tom,
> 
> The stability network is a not really necessary for low frequency simulations:
> - the -3dB point is at 507kHz so it has negligible effect on behaviour
> in the audio band
> - it adds extra calculations so simulation time is a bit longer
> (important when running on crusty old PCs :) )
> 
> Neil
> 
> 
> On 19 March 2014 15:27, Tom Wiltshire <tom at electricdruid.net> wrote:
>> Mattias Rickardsson followed up my post with a version with some tweaks:
>> 
>> * SSM2164 VCA cell
>> *
>> * taken from Olivier Gillet's msg to synth-diy discussion list 2011-01-29
>> *
>> .SUBCKT SSM2164 IN OUT CV
>> * The two transistors in the input's differential pair have the same base
>> * current, hence the same Vbe. The second transistor is referenced to
>> * ground so IN is virtually grounded.
>> V1 IN 0 0
>> * Models 5k impedance for the CV input
>> R2 CV 0 5k
>> * Stability network
>> R3 IN 1 560
>> C1 1 0 560p
>> * Current gain expression
>> G1 OUT 0 VALUE={-I(V1)*PWR(10, -V(CV) * 1.5)}
>> .ENDS
>> 
>> I'd previously just hung a 5K resistor off the CV input if I'd wanted to model the effect of that, but this tweak makes that unnecessary.
>> Whilst these models are very abstract, the fact is that they work for the majority of stuff you want to do. You can design a filter or VCA with it, and the sim results match the reality. If you start overdriving things and expecting to see distortion effects like you'd see on the real chip, you can forget it.
>> 
>> 
>> HTH,
>> Tom
>> 
>> 
>> On 19 Mar 2014, at 15:12, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
>> 
>>> Sorry Neil,
>>> 
>>> I browsed a lot on the web on spice simulation helps.
>>> I should have tought this would have been
>>> a topìc in SynthDIY..
>>> I google since 2 days on a lot of topics
>>> regarding Linear Technologies LTspice I just installed 3 days ago.
>>> I'm newbie on that simulation world subject
>>> so excuse my lasts DIY repetitive requests..
>>> 
>>> JP
>>> 
>>> Le 2014-03-19 10:22, Neil Johnson a écrit :
>>>> Jean-Pierre Desrochers wrote:
>>>>> Ok, so if there is any simplified spice model
>>>>> out there of the SSM2164 that works for someone,
>>>>> and would share.. I'm in.
>>>> Since you seem incapable of using google or the synth-diy mailing list
>>>> archive, try this:
>>>> http://dropmix.xs4all.nl/pipermail/synth-diy/2014-February/042973.html
>>>> Neil
>>>> --
>>>> http://www.njohnson.co.uk
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>> 
> 
> 
> 
> -- 
> --
> http://www.njohnson.co.uk




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