Re: [IBIS-Users] Bus Switch IBIS Models

More exactly, IBIS does not have time profile data to model the transition
of a series switch between on and off states. It is certainly possible to
convert the IBIS series switch model data to a circuit model using table
elements, in which a control signal makes the switch transition dynamically
from on to off and vice-versa. The switching time profile would have to be
set by the control signal. I believe the Cadence implementation works this
way, but I have heard of only one instance of someone using the capability
(experimentally).

I agree with Tim that automation of [Series Switch Groups] and on/off
control at the EDA tool end is lacking. I think Tim is asking the right
question, ³does anyone really need it?²

Mike

On 10/22/10 10:25 AM, "Arpad Muranyi" <Arpad_Muranyi@mentor.com> wrote:

> Tim,
>
> IBIS doesn¹t support modeling the transitions between the On/Off state.
> The assumption is that this is not changing during simulations. There
> is no information in the models that describes how these devices would
> transition from one state to the other. We would need something like
> the V-t tables in order to do that, but they don¹t exist for this
> purpose.
>
> Arpad
> =======================================================================
>
>
> From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of
> Timothy Coyle
> Sent: Thursday, October 21, 2010 11:35 AM
> To: ibis-users@eda.org
> Subject: [IBIS-Users] Bus Switch IBIS Models
>
> Hi,
> When you have MOSFET switch and model it using [Series Mosfet] keyword in IBIS
> there are two ways to pin map it. The first way is to use [Model] Series and
> just use [Series Pin Mapping] and this assumes that the switch is always in On
> state. The other way is to use [Model] Series_switch with [Series Pin Mapping]
> and [Series Switch Groups] and this way there can be configured On and Off
> states. However I have found that most simulation/cad tools do not fully
> support [Series Switch Groups] without manual modification by end user.
> Modeling the switch as a Series device just Series Pin Mapping seems to be the
> default supported state.
>
> Has anyone else seen this issues of Series Switch Groups not being supported?
> Even when I do some modifications for a tool to support it many do not seem to
> use the Off state data. I would also be interested to hear of the simulation
> usage case where someone needs the ability to switch between On and Off
> states.
>
> Thanks,
>
> Timothy Coyle
> President
> Signal Consulting Group LLC
> 405 Western Ave #430
> South Portland, ME 04106
> Tel: 617.297.2566
> Email: tim.coyle@siconsultant.com <mailto:tim.coyle@siconsultant.com>
> Web: http://www.siconsultant.com <http://www.siconsultant.com/>
> SharkSim <http://www.sharksim.com/> - Signal Integrity IBIS Modeling Software
>

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