Buffer issue resolution document (bird) bird id#number: 23. Issue title

IBIS Specification Change Template, Rev. 1.0

BUFFER ISSUE RESOLUTION DOCUMENT (BIRD)


BIRD ID#NUMBER: 123.5

ISSUE TITLE: IBIS-AMI New Reserved Parameters for Jitter/Noise

REQUESTOR: Walter Katz, Mike Steinberger, Todd Westerhoff, SiSoft

DATE SUBMITTED: October 20, 2010

DATE REVISED: April 1, 20112; January 3, 2012, June 11, 2012; October 23, 2012, December 28, 2012

DATE ACCEPTED BY IBIS OPEN FORUM: January 11, 2013
ANALYSIS PATH/DATA THAT LED TO SPECIFICATION:
Model developers and EDA vendors building IBIS-AMI models using the IBIS 5.0 specification have come across a number of modeling issues that are not addressed in IBIS 5.0. In order to deliver models and EDA tools that meet end-user demands for model accuracy and functionality, EDA vendors have defined "extensions" to add new capabilities to IBIS-AMI models. Unfortunately, EDA vendors have had to use proprietary (and different) syntax to add these capabilities to models, limiting model portability between different EDA tools.
This BIRD proposes new syntax for the .ami control file that improves model functionality and accuracy. Including this syntax in the IBIS standard will allow creation of accurate, compliant IBIS-AMI models that are readily portable between commercial EDA simulators.
The parameters defined in this document are to be added in Section 6c of the IBIS 5.0 specification as new Reserved_Parameters.
Jitter, Noise and Clock Modeling

Tx_Rj, Tx_Dj, Tx_Sj, Tx_Sj_Frequency, Rx_Clock_Recovery_Mean, Rx_Clock_Recovery_Rj,

Rx_Clock_Recovery_Dj, Rx_Clock_Recovery_Sj, Rx_Clock_Recovery_DCD, Rx_Rj, Rx_Dj, Rx_Sj, Rx_DCD, and Rx_Noise.
There are three sources of jitter that are accounted for using the parameters introduced in this BIRD; Tx Jitter, Rx Clock Data Recovery (CDR) Jitter and Rx Reference Clock Jitter. The Rx CDR has the ability to filter low frequency Tx Jitter and Rx Reference Clock Jitter. The parameters defined in this BIRD assume that the three sources of jitter are independent. IBIS 5.0 already defines parameters Tx_Jitter, Tx_DCD and Rx_Clock_PDF. Tx_DCD is clarified in this BIRD. The parameters Tx_Rj, Tx_Dj, Tx_Sj, and Tx_Sj_Frequency have similar functionality to the existing Tx_Jitter, but offer more granularity in defining the various components of Tx Jitter. Similarly,Rx_Clock_Recovery_Mean, Rx_Clock_Recovery_Rj, Rx_Clock_Recovery_Dj, Rx_Clock_Recovery_Sj, and Rx_Clock_Recovery_DCD offer increased granularity in defining the CDR behavior when doing statistical analysis, and when Rx AMI_GetWave does not return clock_times. Rx_Rj, Rx_Dj, Rx_Sj, and Rx_DCD describe jitter components that do not exist in IBIS 5.0, and offer the model maker a means to inform the EDA tool about how much extra jitter it should add to sampling instants. That is, these parameters indicate how much, as well as what type of, jitter is present in the actual device, but not reflected in the model. Rx_Noise is unique among the parameters being introduced by this BIRD, in that it describes variations in the amplitude of the received signal, as opposed to variations in the time of sampling instants.
There are other possible methods of describing jitter. These include defining Tx and Rx Jitter Spectral Density distributions and applying Rx Jitter explicitly as reference clock transition times.These advanced methods of handling jitter are left for a future BIRD.
Each parameter defined in the BIRD has included both a verbal and a mathematical description of how that parameter would affect the Tx transition times, Rx CDR and Rx jitter not accounted for in the CDR. In the AMI statistical flow, these impairments are treated as distributions which affect both the clock PDF and statistical eye. In the AMI time domain flow, the EDA tool may apply these jitter parameters directly to the Tx stimulus input and the Rx clock_times using the given equations. Since these jitter parameters are independent, the EDA tool may use other statistical methods to account for these impairments.
Please note that even if no intrinsic jitter were present in the Tx and Rx, one would still experience an eye that has apparent jitter at the Rx data decision point. This jitter is caused by ISI, which is, typically, non-zero despite the efforts of Tx and Rx Equalization.
The model maker may assume that any and all non-zero values passed in these parameters will be used by the EDA tool in one of the following two phases:

1) Input stimulus generation, or

2) Post-processing of simulation results.
The definition of Tx_DCD is clarified, and the allowed Usage is changed to Info.

ANY OTHER BACKGROUND INFORMATION:
BIRD123.5 Removes removes Usage Out from Tx_Jitter to conform to Table 1.
The Table 1 clause “for information only” is removed
When implemented, the Editing committee might make some adjustment to position the all of the parameters related to Jitter and Noise into one section. The Editing Committee can add differences between existing rules for Version 5.1 and higher versions (e.g., for Tx_Jitter and Tx_DCD) and also add the version number for which the new parameters are legal.


Change the following part of Tx_Jitter Descriptor Usage on page 187
Parameter: Tx_Jitter

Required: No

Descriptors:

Usage: Info, Out

Type: Float, UI

Format: Gaussian, Dual-Dirac, DjRj, Table

Default: (Illegal)

Description:

To
Parameter: Tx_Jitter

Required: No

Descriptors:

Usage: Info

Type: Float, UI

Format: Gaussian, Dual-Dirac, DjRj, Table

Default: (Illegal)

Description:

Change the following Tx_DCD Descriptor Usage and other texttext on page 188
Parameter: Tx_DCD

Required: No

Descriptors:

Usage: Info, Out

Type: Float, UI

Format: Value, Range, Corner, List, Increment, Steps

Default: >

Description:

Definition: Tx_DCD (Transmit Duty Cycle Distortion) tells the EDA tool the maximum deviation of the duration of a transmitted pulse as a fraction of the nominal pulse width. Entries are assumed to be in units of seconds when declared as Type Float.
To:
Parameter: Tx_DCD

Required: No

Descriptors:

Usage: Info

Type: Float, UI

Format: Value, Range, Corner, List, Increment, Steps

Default: >

Description:

Definition: Tx_DCD (Transmit Duty Cycle Distortion) defines half the peak to peak clock duty cycle distortion to be added to the behavior implemented by the EDA tool by modifying the stimulus input or by post processing the simulation
Time(n)=n*bit_time+Tx_DCD*(-1.0)^n

n*bit_time is the ideal time of the nth clock.

Time(n) is the time of the nth clock modified when creating input waveforms for the Tx.
Entries are assumed to be in units of seconds when declared as Type Float. Note that all equations using jitter parameters that can be defined as UI shall be assumed to seconds in these formulae.
The following text is added immediately before Table ? on page ???: Jitter, Noise and Clock Parameters
The following optional Reserved Parameters are used to specify impairments for the transmitter output. These budgets specify the impairment as measured at the TX output (i.e. the transmitter output is expected to be directly modulated by these amounts). This data is used by the simulator to either modify the input stimulus presented to the algorithmic model or when post-processing the results from the model; the budget values specified by these parameters are not passed directly to the model itself.

Parameter: Tx_Rj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The standard deviation of a white Gaussian phase noise process at the transmitter which is to be added to the behavior implemented by the EDA tool by modifying the stimulus input or by post processing the simulation results. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: Time(n)=n*bit_time+Tx_Rj*gaussian_rand()

gaussian_rand() is a function that returns floating point numbers between -inf and +inf. The distribution of these numbers shall be a white Gaussian distribution centered at 0.0 with a standard deviation of 1.0. The EDA tool can protect against abs(Tx_Rj*gaussian_rand())>0.5UI.

Example:

(Tx_Rj (Usage Info)(Corner 0.005 0.006 0.004)(Type UI)

(Description "Tx Random Jitter in UI."))

Parameter: Tx_Dj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The worst case half the peak to peak variation at the transmitter implemented by the EDA tool by modifying the stimulus input or by post processing the simulation results. Tx_Dj shall include all deterministic and uncorrelated bounded jitter that is not accounted for by Tx_DCD, and Tx_Sj. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: Time(n)= n*bit_time+2.0*Tx_Dj*rand()

rand() is a function that returns floating point numbers between -0.5 and

+0.5 with white uniform distribution.

Example:

(Tx_Dj (Usage Info)(Value 0.1)(Type UI)

(Description "Tx Bounded Jitter in UI."))

Parameter: Tx_Sj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: Half the peak to peak amplitude of a sinusoidal jitter which is to be added to the behavior implemented directly by the transmitter model.

Usage Rules: If Tx_Sj_Frequency is not assigned (either in the model or by the user), Tx_Sj should be ignored. Entries are assumed to be in units of seconds when declared as Type Float.

Other Notes: Time(n)=n*bit_time+Tx_Sj*sin((n*bit_time*2.0*Pi)*Tx_Sj_Frequency)

Example:

(Tx_Sj (Usage Info)(Corner 0.005 0.006 0.004)(Type UI)

(Description "Tx Sinosoidal Jitter in UI."))


Parameter: Tx_Sj_Frequency

Required: No

Descriptors:

Usage: Info

Type: Float

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The frequency, in Hertz, of the sinusoidal jitter at the transmitter.

Usage Rules: If Tx_Sj_Frequency is not assigned (either in the model or by the user), Tx_Sj should be ignored.

Other Notes: Time(n)=n*bit_time+Tx_Sj*sin((n*bit_time*2.0*Pi)*Tx_Sj_Frequency)

Examples:

(Tx_Sj_Frequency (Usage Info)(Corner 6.5E7 6.5E7 6.5E7)(Type Float)

(Description "Tx Sinusoidal Jitter Frequency in Hz."))

The following optional Reserved Parameters are used to specify characteristics of the receiver's recovered clock. This data is used by the simulator when post-processing the results from the model when the model does not return clock_times, or when Rx AMI_GetWave is not used; the budget values specified by these parameters are not passed directly to the model itself. For Rx models that do return clock_times by AMI_GetWave, these parameters represent the amount of jitter THAT HAD ALREADY BEEN IMPLEMENTED BY RX AMI_GETWAVE AND ALREADY INCLUDED IN THE RETURNED clock_times. For this reason, the EDA platform should NOT apply these jitter parameters again to the Rx clock_times. These parameters are provided by the model creator to the EDA platform and end users for the sole purpose that these jitters can be properly accounted for when Rx AMI_GetWave is NOT used or Rx clock_times was not returned, in which cases the EDA platform is responsible to apply these jitters to the Rx output."

"Rx_Clock_Recovery_Mean" is an AMI parameter of Type either Float or UI, Format

either Value, List, Range, Corner, Increment, or Steps, and Usage Info which defines

a static offset, in seconds or UI, between the recovered clock and the point half

way between the PDF medians of consecutive eye zero crossings.

Parameter: Rx_Clock_Recovery_Mean

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: A static offset between the recovered clock and the point half way between the PDF medians of consecutive eye zero crossings. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time=ideal_time+Rx_Clock_Recovery_Mean

ideal_time half way between the median of the eye crossing 0.0 on both sides of the eye.

Examples:

(Rx_Clock_Recovery_Mean (Usage Info)(Value 0.05)

(Type UI)(Description "Recovered Clock offset in UI."))

Parameter: Rx_Clock_Recovery_Rj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The standard deviation of a Gaussian phase noise exhibited by the recovered clock and included in the clock_times vector returned by the AMI_GetWave function. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time=ideal_time+Rx_Clock_Recovery_Rj*gaussian_rand()

Examples:

(Rx_Clock_Recovery_Rj (Usage Info)(Corner 0.005 0.006 0.004)

(Type UI)(Description "RX Random Clock Jitter in UI."))


Parameter: Rx_Clock_Recovery_Dj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The worst case half the peak to peak variation of the recovered clock. Rx_Clock_Recovery_Dj shall include all deterministic and uncorrelated bounded jitter that is included in the clock_times vector returned by the AMI_GetWave function and not accounted for by Rx_Clock_Recovery_DCD and Rx_Clock_Recovery_Sj. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time = ideal_time + 2.0*Rx_Clock_Recovery_Dj*rand()

Example:

(Rx_Clock_Recovery_Dj (Usage Info)(Value 0.1)(Type UI)

(Description "Tx Bounded Jitter in UI."))


Parameter: Rx_Clock_Recovery_Sj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: Half the peak to peak variation of a sinusoidal phase noise exhibited by the recovered clock and included in the clock_times vector returned by the AMI_GetWave function. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time = ideal_time + Rx_Clock_Recovery_Sj*sin(Pi*rand())

Example:

(Rx_Clock_Recovery_Sj (Usage Info)(Corner 0.05 0.07 0.4)(Type UI)

(Description "RX Sinusoidal Jitter in UI."))


Parameter: Rx_Clock_Recovery_DCD

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: Half the peak to peak variation of a clock duty cycle distortion exhibited by the recovered clock and included in the clock_times vector returned by the AMI_GetWave function. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time=ideal_time+Rx_Clock_Recovery_DCD*(-1.0)^n

Example:

(Rx_Clock_Recovery_DCD (Usage Info)(Corner 0.008 0.016 0.005)

(Type UI)(Description "RX Duty Cycle Distortion in UI."))

Other Notes:

Rx_Clock_Recovery_Dj may be used as a repository of all deterministic jitter. However any combination of Rx_Clock_PDF, Rx_Clock_Recovery_Dj, Rx_Clock_Recovery_Sj and Rx_Clock_Recovery_DCD is allowed, but the the model maker should make sure that jitter components are not double counted. Total clock recovery deterministic jitter that is included in the clock_times vector returned by the AMI_GetWave function should be equal to the sum of Rx_Clock_PDF, Rx_Clock_Recovery_Dj, Rx_Clock_Recovery_Sj and Rx_Clock_Recovery_DCD.

Total Clock Recovery Deterministic Jitter accounted for in clock_times:

actual_time = ideal_time + 2.0*Rx_Clock_Recovery_Dj*rand()

+ Rx_Clock_Recovery_Sj*sin(Pi*rand())

+ Rx_Clock_Recovery_DCD*(-1.0)^n

+ Rx_Clock_PDF>

The following optional Reserved Parameters are used to modify the statistics

associated with receiver's recovered clock. These parameters are used to account for

jitter that is not included in either the clock_times returned by Rx AMI_GetWave or

the Rx_Clock_Recovery parameters. This data is used by the simulator when post-

processing the results from the model; the budget values specified by these

parameters are not passed directly to the model itself.

Parameter: Rx_Rj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The standard deviation of a Gaussian phase noise driven by impairments external to the receiver that are input to the RX CDR, but are not included in the CDR clock_times output. This phase noise is to be accounted for by the EDA tool, in both Statistical and Time-Domain simulations. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: clock_times(n)= time+Rx_Rj *gaussian_rand()

time = ideal_time in Statistical, and Time-Domain when clock_times(n) is not available

= clock_times(n) in Time-Domain when clock_times(n) is returned by Rx AMI_Getwave

Example:

(Rx_Rj (Usage Info)(Corner 0.005 0.006 0.004)(Type UI)

(Description "Rx Random Jitter in UI."))

Parameter: Rx_Dj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The worst case half peak to peak variation of the recovered clock, not including the random jitter specified by Rx_Rj, Rx_Sj, or Rx_DCD. Rx_Dj shall include all deterministic and uncorrelated bounded jitter that is not accounted for by Rx clock_times, Rx_Rj, or Rx_Clock_Recovery parameters. This phase noise is to be accounted for by the EDA tool in both Statistical and Time-Domain simulations. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time = time + 2.*Rx_Dj*rand()

time = ideal_time in Statistical, and Time-Domain when clock_times(n) is not available

= clock_times(n) in Time-Domain when clock_times(n) is returned by Rx AMI_Getwave

Example:

(Rx_Dj (Usage Info)(Value 0.1)(Type UI)

(Description "Tx Bounded Jitter in UI."))


Parameter: Rx_Sj

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: Half the peak to peak variation of a sinusoidal phase noise, but are not included in the CDR clock_times output. This phase noise is to be accounted for by the EDA tool in both Statistical and Time-Domain simulations. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time = time+ Rx_Sj*sin(Pi*rand())

time = ideal_time in Statistical, and Time-Domain when clock_times(n) is not available

= clock_times(n) in Time-Domain when clock_times(n) is returned by Rx AMI_Getwave

Example:

(Rx_Sj (Usage Info)(Corner 0.05 0.07 0.04)(Type UI)

(Description "RX Sinusoidal Jitter in UI."))

Parameter: Rx_DCD

Required: No

Descriptors:

Usage: Info

Type: Float or UI

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: Half the peak to peak variation of a clock duty cycle distortion. This phase noise is to be accounted for by the EDA tool in both Statistical and Time-Domain simulations. Entries are assumed to be in units of seconds when declared as Type Float.

Usage Rules:

Other Notes: actual_time = time + Rx_DCD*(-1.0)^n

n is the nth clock

time = ideal_time in Statistical, and Time-Domain when clock_times(n) is not available

= clock_times(n) in Time-Domain when clock_times(n) is returned by Rx AMI_Getwave

Example:

(Rx_DCD (Usage Info)(Corner 0.008 0.016 0.005)(Type UI)

(Description "RX Duty Cycle Distortion in UI."))
Other Notes:

Rx _Dj may be used as a repository of all deterministic jitter not included in clock_times. However any combination of Rx_ Dj, Rx_ Sj and Rx_ DCD is allowed, but the the model maker should make sure that jitter components are not double counted. Total clock recovery deterministic jitter that is not included in the clock_times vector returned by the AMI_GetWave function should be equal to the sum of Rx_ Dj, Rx_ Sj and Rx_ DCD.

Total Clock Recovery Deterministic Jitter not acounted for in clock_times:

actual_time = time + 2.*Rx_Dj*rand()

+ Rx_Sj*sin(Pi*rand())

+ Rx_DCD*(-1.0)^n

The following optional Reserved Parameter is used to modify the statistics associated with the data input to the receiver's sampling latch (a.k.a. 'slicer'). This data is used by the simulator when post-processing the results from the model; the budget values specified by this parameter are not passed directly to the model itself.

Parameter: Rx_Noise

Required: No

Descriptors:

Usage: Info or Out

Type: Float

Format: Value, List, Range, Corner, Increment, or Steps

Default: >

Description:

Definition: The standard deviation, in Volts, of a white Gaussian random process, which is to be added by the EDA tool to the signal measured at the sampling latch of a receiver.

Usage Rules: If Rx_Noise is Usage Out, then the EDA tool shall use the value returned by Rx AMI_Init if Rx AMI_GetWave is not used. If Rx AMI_GetWave is used, then the EDA tool may apply the value returned by each AMI_GetWave call to the waveform returned by that call to AMI_GetWave, or use the average value of Rx_Noise returned by all calls to AMI_GetWave (after Ignore_Bits), or the value of Rx_Noise returned by the last call to AMI_GetWave.

Other Notes: wave(t)=wave(t)+Rx_Noise*gaussian_rand()

wave(t) is the waveform returned by Rx AMI_GetWave

Example:

(Rx_Noise (Usage Info)(Value .010) (Type Float)

(Description "Rx amplitude noise at sampling latch in Volts."))

Note:

The "Rx_Clock_Recovery Parameters" (Rx_Clock_PDF, Rx_Clock_Recovery_Mean, Rx_Clock_Recovery_Rj, Rx_Clock_Recovery_Dj, Rx_Clock_Recovery_Sj and Rx_Clock_Recovery_DCD, should be used by the simulator when analyzing the output of Rx AMI_Init (for statistical analysis) or Rx AMI_GetWave (time domain) when Rx AMI_GetWave does not return clock_times. When Rx AMI_GetWave returns clock_times, the simulator should not use the "Rx_Clock_Recovery Parameters".
Note:

The "Rx Jitter Parameters" (Rx_Rj, Rx_Dj, Rx_Sj and Rx_DCD, should be used by the simulator when analyzing the output of either Rx AMI_Init (for statistical analysis) or Rx AMI_GetWave (for time domain analysis).

Tables summarizing the rules for the jitter, noise and sensitivity parameters for information only.
*****************************************************************************
+------------------------+-------------------+

| General Rules | Allowed Usage |

============================================================================

| Reserved Parameter | Required Default | Info In Out InOut |

+-----------------------------+------------------------+-------------------+

| Tx_Jitter | No No Jitter | X |

| Tx_Dj | No 0 | X |

| Tx_Rj | No 0 | X |

| Tx_Sj | No 0 | X |

| Tx_DCD | No 0 | X |

| Tx_Sj_Frequency | No Undefined | X |

| Rx_Receiver_Sensitivity | No 0 | X X |

| Rx_Clock_PDF | No Clock Centered | X |

| Rx_Clock_Recovery_Mean | No 0 | X |

| Rx_Clock_Recovery_Dj | No 0 | X |

| Rx_Clock_Recovery_Rj | No 0 | X |

| Rx_Clock_Recovery_Sj | No 0 | X |

| Rx_Clock_Recovery_DCD | No 0 | X |

| Rx_Dj | No 0 | X |

| Rx_Rj | No 0 | X |

| Rx_Sj | No 0 | X |

| Rx_DCD | No 0 | X |

| Rx_Noise | No 0 | X X |

+-----------------------------+------------------------+-------------------+

Table 1: General Rules and Allowed Usage for Reserved Parameters

+-------------------------------------------+

| Data Type |

===========================================================================

| Reserved Parameter | Float | UI | Integer | String | Boolean |

+-----------------------------+-------+------+---------+--------+---------+

| Tx_Jitter | X X |

| Tx_Dj | X X |

| Tx_Rj | X X |

| Tx_Sj | X X |

| Tx_DCD | X X |

| Tx_Sj_Frequency | X |

| Rx_Receiver_Sensitivity | X |

| Rx_Clock_PDF | X X |

| Rx_Recovery_Mean | X X |

| Rx_Clock_Recovery_Dj | X X |

| Rx_Clock_Recovery_Rj | X X |

| Rx_Clock_Recovery_Sj | X X |

| Rx_Clock_Recovery_DCD | X X |

| Rx_Dj | X X |

| Rx_Rj | X X |

| Rx_Sj | X X |

| Rx_DCD | X X |

| Rx_Noise | X |

+-----------------------------+-------------------------------------------+
Table 2: Allowed Data Types for Reserved Parameters

+---------------------------------------+

| Data Format |

=======================================================================

| Reserved Parameter | V | R | C | L | I | S | G | D | D | T |

| | a | a | o | i | n | t | a | u | j | a |

| | l | n | r | s | c | e | u | a | R | b |

| | u | g | n | t | r | p | s | l | j | l |

*| | e | e | e | | e | s | s | - | | e |

*| | | | r | | m | | i | D | | |

*| | | | | | e | | a | i | | |

*| | | | | | n | | n | r | | |

*| | | | | | t | | | a | | |

*| | | | | | | | | c | | |

+-----------------------------+---+---+---+---+---+---+---+---+---+---+

| Tx_Jitter | X X X X |

| Tx_Dj | X X X X X X |

| Tx_Rj | X X X X X X |

| Tx_Sj | X X X X X X |

| Tx_DCD | X X X X X X |

| Tx_Sj_Frequency | X X X X X X |

| Rx_Receiver_Sensitivity | X X X X X X |

| Rx_Clock_PDF | X X X X |

| Rx_Recovery_Mean | X X X X X X |

| Rx_Clock_Recovery_Dj | X X X X X X |

| Rx_Clock_Recovery_Rj | X X X X X X |

| Rx_Clock_Recovery_Sj | X X X X X X |

| Rx_Clock_Recovery_DCD | X X X X X X |

| Rx_Dj | X X X X X X |

| Rx_Rj | X X X X X X |

| Rx_Sj | X X X X X X |

| Rx_DCD | X X X X X X |

| Rx_Noise | X X X X X X |

+-----------------------------+---------------------------------------+

Table 3: Allowed Data Format for Reserved Parameters
*****************************************************************************
With the exception of the "Table" format, the Tx_Jitter parameter has been essentially superseded by the Reserved_Parameters Tx_Rj, Tx_Dj, Tx_Sj, Tx_Sj_Frequency, and Tx_DCD, which enable SerDes transmitter jitter to be specified in greater detail. It is recommended for AMI model developers to use these preferred jitter parameters when possible instead of Tx_Jitter.With the exception of the "Table" format, the Rx_Clock_PDF parameter has been essentially superseded by the Reserved_Parameters Rx_Clock_Recovery_Rj, Rx_Clock_Recovery_Dj, Rx_Clock_Recovery_Sj, and Rx_Clock_Recovery_DCD, which enable SerDes receiver jitter to be specified in greater detail. It is recommended for AMI model developers to use these preferred jitter parameters when possible instead of

Rx_Clock_PDF.

*****************************************************************************
ANALYSIS PATH/DATA THAT LED TO SPECIFICATION
The parameters defined in this BIRD came from commercial IBIS-AMI model development efforts where new functionality was needed to meet customer expectations for model functionality, accuracy and performance. The parameters in this BIRD were defined by SiSoft and its semiconductor partners. These parameters are being contributed to IBIS to ensure IBIS-AMI model accuracy and portability.
BIRD123.5 Removes removes Usage Out from Tx_Jitter to conform to Table 1.
The Table 1 clause “for information only” is removed
When implemented, the Editing committee might make some adjustment to position the all of the parameters related to Jitter and Noise into one section. The Editing Committee can add differences between existing rules for Version 5.1 and higher versions (e.g., for Tx_Jitter and Tx_DCD) and also add the version number for which the new parameters are legal.

*****************************************************************************

ANY OTHER BACKGROUND INFORMATION:
This BIRD is being requested by the following IBIS users and model developers, in conjunction with the authors:
Cisco Systems: Upen Reddy, Doug White

Ericsson: Anders Ekholm

Broadcom: Yunong Gan

IBM: Adge Hawes

TI: Alfred Chong, Srikanth Sundaram

*****************************************************************************