BIRD100: A Series of Package Choices

1
BIRD100A Series of Package Choices

• Michael Mirmak
• Intel Corp.
• Chair, EIA IBIS Open Forum

2
Status

• Creation of BIRD100 has hit a wall
• Intended to define IBIS-ICM link syntax
• What the draft BIRD100 includes today
• instance_name -- a subparameter of Pin
• Permits multiple Models on one pin, and
  multiple pins tied to a single Model instance
• Pad a subparameter of Pin Numbers
• Permits traditional Package Model constructs to
  connect to multiple Models
• Notes on ICM Naming Convention
• A set of instructions on properly naming ICM
  nodes to map to Model and External Model
  connection points

3
The Problem

• IBIS ambiguities force choices for ICM linking
• Need definitive statements on the application of
  and relationships between several keywords
• Pin Mapping and package models
• POWER and GND Pins and package models
• Package models and Pins / Models
• Additionally
• For what IBIS constructs should ICM be available?
• For what IBIS constructs should traditional
  packages be available?
• Interactions to check
• IBIS buffer construct (native, E. Model, E.
  Circuit)
• Pin modeling of power/ground (Pin uses POWER or
  not?)
• Pin Mapping (used or not?)
• Package model type (Package, Package Model,
  ICM, R_pin, etc.)
• BIRD100 constructs (instance_name used or not?)
• 96 different combinations in all

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Key Questions

• BIRD100 as written is incomplete
• Not all IBIS 4.1 Fig. 12 cases addressed
• The following slides ask key questions which must
  be answered to complete BIRD100
• Answers to these questions will impact how
  BIRD95, AMS are implemented
• These may also affect tools currently
  implementing Pin Mapping and other package
  keywords
• Keep in mind potential EMI and non-PC
  applications (JEITA requests)

5
Figure 12 (top)

6
Figure 12 (bottom)

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Q1 Pin Mapping

• Pin Mapping
• What is the relationship between Pin Mapping
  and package models (Package, Package Model,
  R_pin)?
• Where are Pin Mapping connections made?
• At the buffer rail? (option a below)
• If so, packages sit between Pin Mapping
  busses and pins
• At the pin, with ideal shorts? (option b below)
• If so, packages sit between Pin Mapping
  busses and individual buffer rails
• R_pin makes less sense in this version
• May we assume Circuit Call prohibits Pin
  Mapping?
• For just the affected pins?
• For the entire component?
• Will instance_name work with Pin Mapping?
• We cannot avoid a choice here

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(a) Pin Mapping as On-die

• Package model associated with pins
• Pin Mapping is between packages and buffers

Package, Pin
Pin Mapping
Package Model
A2 (POWER)
pullup_ref
Digital Port
A1
pulldown_ref
A3 (GND)
9
(b) Pin Mapping as Pin Shorts

• Pin Mapping shorts pins together

Pkg
A2 (POWER)
pullup_ref
Pkg
A1
A5 (POWER)
Pkg
A3 (GND)
Pkg
pulldown_ref
Digital Port
Pkg
A4
A6 (GND)
Pkg
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Q2 Traditional Packages

• Traditional Package Models
• Package, Package Model and R_pin, etc.
• How do these relate to power/ground connections?
• Example
• Pin A1 is defined POWER. It has R_pin, L_pin,
  C_pin associated with it (this is not prohibited)
• Is the package model connected to this pin?
• If so, where is the other end of the package?
• If not, is pin A1 a direct short (and if so, to
  where)?
• Same question applies to Package Model
• Endpoint is assumed the die pad which one?
• Currently, only Pin Mapping resolves this
  situation
• Without 4.1 port definitions (A_puref) or Pin
  Mapping, package details on power are meaningless

11
Q3 IBIS 4.1 Ports

• IBIS 4.1 creates standard ports (A_puref) for E.
  Model
• Same port names can be applied to E. Circuit
• Should we allow use of A_puref, etc. ports for
  package definitions, Pin Mapping, etc.?
• Example Pin A1 (POWER) connects to A_puref for
  I/O pin A2
• If not, External Model cannot connect to
  packages without ICM
• See Fig. 12 in IBIS 4.1 where do these ports go?
• How do Pin Mapping and Package Model connect
  to A_puref?
• Option 1 assume A_puref pullup_ref
• Shorts all External Model supplies
• This prohibits multiple buffer instances now in
  BIRD100
• Option 2 allow A_puref in Pin Mapping syntax
• Option 3 allow instance_name.A_puref in Pin
  Mapping
• Also allows Package Model to use ports
  multiple instances

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Q4 IBIS 4.1 Ports for Model

• IBIS 4.1 suggests ports apply to native Models
• Native Model Model without External
  Model
• Do we allow A_puref to be used with native
  Models?
• Should instance_name be permitted alongside these
  constructs?
• If so, External Model just got expanded to work
  with multiple instantiations (not necessarily bad)

13
Proposals

• Prohibit Pin Mapping and External Circuit
• Prohibit Pin Mapping and External Model
• Document Pin Mapping as connecting packages to
  buffers (packages connect to pins)
• Permit use of ports with traditional IBIS
• Example, A_puref for Model without E. Model
• Permit use of Package Model with E. Model
• Allow dot notation Pad subparameter in Package
  Model
• Example Padmyinstance.A_puref, where myinstance
  is a specific instance_name under Pin
• Permit ICM for ALL flavors of IBIS (native,
  multi-lingual)
• Model, External Model links must use the die
  node syntax instance_name.port_name
• Integrate ICM parser into IBIS parser
• Raise total IBIS parser fee to 3000
• Permits checking of ICM as Package Model file
• Permit ICM code within an IBIS model