Re: Can't do T-LINE?

Excuse me, but wouldn't that mean that you only will
be able to use one T-line segment as a package
modell ?

That would imply that the package is uniform, and
I would suppose that most packages are not. To get
an accurate model you need multiple T-line segment
models. Is that not possible in IBIS 3.0 ?

        Best Regards /Anders Ekholm
                      Ericsson Telecom

> From owner-ibis@server.vhdl.org Wed May 20 04:46 MET 1998
> From: bobr@emicx.mentorg.com (Bob Ross)
> Date: Tue, 19 May 98 19:03:38 PDT
> To: crokusek@viewlogic.com, ibis@eda.org
> Subject: Re: Can't do T-LINE?
> Cc: bobr@emicx.mentorg.com
> Mime-Version: 1.0
> X-Status: $$$$
> X-UID: 0000001041
>
> Chris:
>
> The L, C, and R parameters are given as CORRESPONDING per unit length values.
> These are multiplied by Len to produce the total distributed values for the
> exact length of T-line that you want.
>
> Whenever Len is not equal to zero, the section is interpreted as
> a distributed section (not a lumped section).
>
> The T-line relationships still hold:
>
> Zo = sqrt(L/C)
> TD = Len * sqrt(LC)
>
> So the electrical information is available for a T-line of whatever length
> you want.
>
> Best Regards,
> Bob Ross
> Interconnectix/Mentor Graphics
>
>
> > Sender: crokusek@qdt.com
> > Date: Tue, 19 May 1998 17:56:15 -0700
> > From: Chris Rokusek <crokusek@viewlogic.com>
> > To: ibis@eda.org
> > Subject: Can't do T-LINE?
>
> > ( I am reposting this question in hopes of a more helpful response )
>
> > Hi All,
>
> > Concerning [Path Description] section in Ver 3.x of .ibs...
>
> > The 'len' parameter is given in 'units' which is 'arbitrary' (i.e. not
> > meters) such that a distributed T-LINE model cannot be built with the
> > proper physical length.
>
> > ** I DO NOT WANT TO BUILD A LUMPED MODEL, I WANT TO BUILD A T-LINE MODEL
> > **
>
> > Is this an oversight or am I not understanding the parameters?
>
> > Best Regards,
>
> > Chris Rokusek
> > Viewlogic Systems
>
> >
> >
> > |=============================================================================
> > | Keyword: [Path Description]
> > | Required: Yes
> > | Description: This keyword allows the user to describe the connection
> > | between the user accessible pins of a part and the pins
> > of the
> > | ICs mounted on that part. Each pin to node connection
> > is
> > | divided into one or more cascaded "sections", where each
> > | section is described in terms of it's L/R/C per unit
> > length.
> > | The Fork and Endfork subparameters allow the path to
> > branch to
> > | multiple nodes, or another pin. A path description is
> > | required for each pin whose signal name is not "GND",
> > "POWER"
> > | or "NC".
> > |
> > | Board Description and IC Boundaries:
> > |
> > | In any system, each part interfaces with another part at
> > some
> > | boundary. Every part model must contain the components
> > | necessary to represent the behavior of the part being
> > modeled
> > | within its boundaries. The boundary definition depends
> > upon
> > | the parts being represented by the model.
> > |
> > | For CARD EDGE CONNECTIONS such as a SIMM or a PC
> > Daughter
> > | Card plugged into a SIMM Socket or Edge Connector, the
> > | boundary should be at the end of the board card edge
> > pads as
> > | they emerge from the connector.
> > |
> > | For any THROUGH-HOLE MOUNTED PART, the boundary will be
> > at the
> > | surface of the board on which the part is mounted.
> > |
> > | SURFACE MOUNTED PART models end at the outboard end of
> > their
> > | recommended surface mount pads.
> > |
> > | If the board level component contains an UNMATED
> > CONNECTOR,
> > | the unmated connector will be described in a separate
> > file,
> > | with its boundaries being as described above for the
> > | through-hole or surface mounted part.
> > |
> > | Sub-Params: Len, L, R, C, Fork, Endfork, Pin, Node
> > | Usage Rules: Each individual connection path (user pin to node(s))
> > | description begins with the [Path Description] keyword
> > and a
> > | path name, followed by the subparameters used to
> > describe the
> > | path topology and the electrical characteristics of each
> > | section of the path. The path name must not exceed 40
> > | characters, blanks are not allowed, and each occurrence
> > of the
> > | [Path Description] keyword must be followed by a unique
> > path
> > | name. Every signal pin (pins other than POWER, GND or
> > NC)
> > | must appear in one and only one path description per
> > [Begin
> > | Board Description]/[End Board Description] pair. Pin
> > names do
> > | not have to appear in the same order as listed in the
> > [Pin
> > | List] table. The individual subparameters are broken up
> > into
> > | those that describe the electrical properties of a
> > section,
> > | and those that describe the topology of a path.
> > |
> > | Section Description Subparameters:
> > |
> > | The Len, L, R, and C subparameters specify the length,
> > the
> > | series inductance and resistance and the capacitance to
> > ground
> > | of each section in a path description.
> > |
> > | Len The physical length of a section. Lengths are
> > given
> > | in terms of arbitrary 'units'. Any non-zero
> > length
> > | requires that the parameters that follow must be
> > | interpreted as distributed elements by the
> > simulator.
> > | L The series inductance of a section, in terms of
> > | 'inductance/unit length'. For example, if the
> > total
> > | inductance of a section is 3.0 nH and the length
> > of
> > | the section is 2 'units', the inductance would
> > be
> > | listed as L = 1.5 nH (i.e. 3.0 / 2).
> > | C The capacitance to ground of a section, in terms
> > of
> > | capacitance per unit length.
> > | R The series DC (ohmic) resistance of a section,
> > in
> > | terms of ohms per unit length.
> > |
> > | Topology Description Subparameters:
> > |
> > | The Fork and Endfork subparameters denote branches from
> > the
> > | main pin-to-node or pin-to-pin connection path. The
> > Node
> > | subparameter is used to reference the pin of a component
> > or
> > | board as defined in a .ibs or .ebd file. The Pin
> > subparameter
> > | is used to indicate the point at which a path connects
> > to a
> > | user visible pin.
> > |
> > | Fork This subparameter indicates that the sections
> > | following (up to the Endfork subparameter) are
> > part
> > | of a branch off of the main connection path.
> > This
> > | subparameter has no arguments.
> > | Endfork This subparameter indicates the end point of a
> > branch.
> > | For every Fork subparameter there must be a
> > | corresponding Endfork subparameter. As with the
> > Fork
> > | subparameter, the Endfork subparameter has no
> > | arguments.
> > | Node reference_designator.pin
> > | This subparameter is used when the connection
> > path
> > | connects to a pin of another, externally defined
> > part.
> > | The arguments of the Node subparameter indicate
> > the
> > | pin and reference designator of the external
> > | component. The pin and reference designator
> > portions
> > | of the argument are separated by a period
> > ("."). The
> > | reference designator is mapped to an external
> > | component description (another .ebd file or .ibs
> > file)
> > | by the [Reference Designator Map] Keyword. Note
> > that
> > | a Node MUST reference a model of a passive or
> > active
> > | component. A Node is not an arbitrary
> > connection
> > | point between two elements or paths.
> > | Pin This subparameter is used to mark the point at
> > which
> > | a path description connects to a user accessible
> > pin.
> > | Every path description must contain at least one
> > | occurrence of the Pin subparameter. It may also
> > | contain the reserved word NC. The value of the
> > Pin
> > | subparameter must be one of the pin names listed
> > in
> > | the [Pin List] section.
> > |
> > | Using The Subparameters to Describe Paths:
> > |
> > | A section description begins with the Len subparameter
> > and
> > | ends with the slash (/) character. The value of the
> > Len, L,
> > | R, and C subparameters and the subparameter itself are
> > | separated by an equals sign (=); whitespace around the
> > equals
> > | sign is optional. The Fork, Endfork, Node and Pin
> > | subparameters are placed between section descriptions
> > (i.e.,
> > | between the concluding slash of one section and the
> > 'Len'
> > | parameters that starts another). The arguments of the
> > Pin and
> > | Node subparameter are separated by white space.
> > |
> > | Specifying a Len or L/R/C value of zero is allowed. If
> > | Len = 0 is specified, then the L/R/C values are the
> > total for
> > | that section. If a non-zero length is specified, then
> > the
> > | total L/R/C for a section is calculated by multiplying
> > the
> > | value of the Len subparameter by the value of the L, R,
> > or C
> > | subparameter. However, as noted below, if a non-zero
> > length
> > | is specified, that section MUST be interpreted as
> > distributed
> > | elements.
> > |
> > | Legal Subparameter Combinations for Section
> > Descriptions:
> > |
> > | A) Len, and one or more of the L, R and C
> > subparameters. If
> > | the Len subparameter is given as zero, then the L/R/C
> > | subparameters represent lumped elements. If the Len
> > | subparameter is non-zero, then the L/R/C subparameters
> > | represent distributed elements and both L and C must be
> > | specified, R is optional.
> > |
> > | B) The first subparameter following the [Path
> > Description]
> > | keyword must be 'Pin', followed by one or more section
> > | descriptions. The path description can terminate in a
> > Node,
> > | another pin or the reserved word, NC.
> > |
> > | Dealing With Series Elements:
> > |
> > | A discrete series R or L component can be included in a
> > path
> > | description by defining a section with L=0 and the
> > proper R or
> > | L value. A discrete series component can also be
> > included in
> > | a path description by writing two back to back node
> > statements
> > | that reference the same component (see the example
> > below).
> > | Note that both ends of a discrete, two terminal
> > component MUST
> > | be contained in a single [Path Description]. Connecting
> > two
> > | separate [Path Description] with a series component is
> > not
> > | allowed.
> > |-----------------------------------------------------------------------------
> > |
> > | An Example Path For a SIMM Module:
> > |
> > [Path Description] CAS_2
> > Pin J25
> > Len = 0.5 L=8.35n C=3.34p R=0.01 /
> > Node u21.15
> > Len = 0.5 L=8.35n C=3.34p R=0.01 /
> > Node u22.15
> > Len = 0.5 L=8.35n C=3.34p R=0.01 /
> > Node u23.15
> > |
> > | A Description Using The Fork and Endfork Subparameters:
> > |
> > [Path Description] PassThru1
> > Pin B5
> > Len = 0 L=2.0n /
> > Len = 2.1 L=6.0n C=2.0p /
> > Fork
> > Len = 1.0 L = 1.0n C= 2.0p /
> > Node u23.15
> > Endfork
> > Len = 1.0 L = 6.0n C=2.0p /
> > Pin A5
> > |
> > | A Description Including a Discrete Series Element:
> > |
> > [Path Description] sig1
> > Pin B27
> > Len = 0 L=1.6n /
> > Len = 1.5 L=6.0n C=2.0p /
> > Node R2.1
> > Node R2.2
> > Len = 0.25 L=6.0n C=2.0p /
> > Node U25.6
> > |
> > |=============================================================================
>
>
>
Received on Thu May 21 03:23:05 1998