Figure 2 – Example of an ICIM-CI model of an electronic board The valid frequency range of the ICIM-CI model is the same as that of the data simulation or measurement used for obtaining
Terms and definitions
For the purposes of this document, the following terms and definitions apply
XML element placed one level below the root element or within another section and that contains one or more XML elements, but no value
3.1.2 parent keyword which is one level above another keyword
3.1.3 child keyword which is one level below another keyword
3.1.4 external terminal terminal of an integrated circuit macro-model which interfaces the model to the external environment of the integrated circuit
EXAMPLE Power supply pins and input/output pins
Note 1 to entry: In this part of IEC 62433, a terminal is by default considered as external unless otherwise stated
[SOURCE: IEC 62433-2:2008, 3.1, modified – Note 1 to entry has been changed, Example has been added]
3.1.5 internal terminal terminal of an integrated circuit macro-model's component which interfaces the component to other components of the integrated circuit macro-model
3.1.6 parser tool for syntactic analysis of data that is encoded in a specified format
Conducted Immunity Markup Language data exchange format for ICIM-CI model
Conducted Immunity Markup Language Base abstract type from which all CIML model components are directly or indirectly derived in the ICIM-CI model definition
DI Disturbance Input input terminal for the injection of RF disturbances
Note 1 to entry: It could be any pin of IC, an input, supply or an output
The disturbance output terminal is affected by the load connected to the disturbance input (DI) terminal, which influences the impedance and transfer characteristics of the power distribution network (PDN) This terminal also outputs a portion of the disturbances received at the DI terminals.
OO Observable Output output terminal where the immunity criteria are monitored during the test
GND Ground terminal terminal that is used as reference for return path
PDN Passive Distribution Network block that describes the impedance network of one or more ports of the integrated circuit
IB Immunity Behaviour block that describes the internal immunity behaviour of the IC
IBC Inter Block Coupling block that describes the coupling network between different PDN blocks within an IC
VNA Vector Network Analyzer instrument to measure complex network parameters such as S-, Y- or Z- parameters in the frequency domain
Radio Frequency Injection Probe probe for injecting RF disturbances into a pin of an IC allowing measurement of voltage and current
Abbreviations
SPICE Simulation Program with Integrated Circuit Emphasis
Conventions
For the sake of clarity, but with some exceptions, the writing conventions of XML have been used in text and tables
Integrated circuits are experiencing a rise in gate count and integration density, while supply voltages are decreasing This trend, along with reduced distances between on-chip signals and smaller die geometries, contributes to heightened internal crosstalk due to increased unwanted currents in parasitic structures like isolation capacitances As a result, the immunity of integrated circuits is becoming increasingly vital.
To mitigate the heightened risk of reduced integrated circuit (IC) immunity, it is essential to utilize models and simulation tools for optimizing the immunity performance of both the IC and its applications.
This part of IEC 62433 describes such macro-models for simulating immunity behaviour at the
The ICIM-CI model is designed to predict electromagnetic immunity at the application level, utilizing files that detail the Power Distribution Network (PDN) and the Interconnect Block (IB) with data on electromagnetic disturbances affecting observable signals While the PDN is treated as linear, the model accounts for the inherent non-linearity of the integrated circuit (IC) within the IB Users are advised to implement a failure criterion for the observable signal based on their specific requirements.
The ICIM-CI model data is structured in a clear nested format using XML, known as Conducted Immunity Markup Language (CIML), to facilitate straightforward and universal access to the model Preliminary definitions for the XML representation can be found in Annex A.
General
The internal structure of an integrated circuit (IC) consists of two main components: passive parts, which include parasitic elements of pins, bondings, tracks, and ESD protection that transmit external disturbances to the internal blocks, and active parts, such as the CPU core, clock system, memory, and analogue blocks, which are particularly sensitive to these incoming disturbances.
The ICIM-CI model consists of a set of data describing these two parts:
• PDN: the Passive Distribution Network is a multi-port circuit It is composed of four different terminals:
– DI: Terminals to which disturbances are applied,
– DO: Terminals that can influence the impedance of the DI terminals and consequently receive a part of the disturbance applied on the DI terminals,
– GND: PDN shall have one or more ground terminals (such as digital ground, analogue ground),
– Internal terminals: Terminals that can influence the impedance of the DI terminals and are internal to the IC (at chip-level)
The Immunity Behaviour (IB) component outlines the response of the Integrated Circuit (IC) to applied disturbances, referencing one ground terminal of the Power Distribution Network (PDN) The immunity criterion is established at terminals known as Observable Outputs (OO), which may or may not be linked to various Design Inputs (DI), depending on the IC's configuration.
NOTE 1 DI, DO, OO and GND terminals are external terminals and are interfaced at pin level These pins connect to the external environment of the IC.
The two OO terminals connect the Power Distribution Network (PDN) to the Input Buffer (IB) These terminals, which are external to the Integrated Circuit (IC), facilitate the acquisition of the IB by assessing the immunity criterion Internally, they are represented within the PDN of the ICIM-CI macro-model.
Figure 1 represents an example of ICIM-CI model structure
Figure 1 – Example of ICIM-CI model structure
The PDN block does not have a direct electrical connection to the IB block, as the PDN represents the input impedance of the DI The power supplied to the DI is determined through simulation, taking into account the PDN and external conditions The IB connects the power entering the DI to an immunity criterion that is observed at the OO terminal This IB is derived from an immunity measurement of the IC, which is conducted by monitoring the OO terminal.
Depending on the IC’s operating conditions and stability, DO terminals may be present One such example is illustrated in Annex B
Various ICIM-CI models can be integrated to effectively represent a complete electronic system, such as an electronic board This proposed framework is also applicable for modeling specific equipment The DO terminal of one ICIM-CI model facilitates connections with the terminals of adjacent ICIM-CI blocks.
Figure 2 illustrates a complete ICIM-CI model of an electronic board, which is represented by three independent ICIM-CI models The models T12 and T21 are interconnected and experience the same disturbance Additionally, the ICIM-CI_1 model transmits a portion of its disturbance to the ICIM-CI_3 model via the T14 (DO) terminal, which links to the T31 (DI) terminal of the ICIM-CI_3 model.
Figure 2 – Example of an ICIM-CI model of an electronic board
The valid frequency range of the ICIM-CI model is the same as that of the data (simulation or measurement) used for obtaining the PDN and IB parts.
PDN description
The PDN consists of passive elements for the package, bonding and on-chip interconnections
The Power Distribution Network (PDN) serves as the input network for the chip's power and signal pins, comprising a complete impedance network It includes input injection terminals (DI), terminals that may affect the impedance of disturbed terminals (DO), and internal terminals The PDN can feature both linear and non-linear components, such as resistance, capacitance, and ESD diode protection However, the PDN data is specified under conditions where the non-linear components remain inactive.
PDN characterizes the coupling path for the RF disturbances, which can undergo filtering and distortion Its impedance can vary considerably with frequency
The Power Distribution Network (PDN) is characterized in the frequency domain through various network parameters One key parameter is the impedance, denoted as Z(f), which represents the ratio of voltage to current at the disturbance input of the network.
PDN It represents the electrical schematic of passive input impedance, often consisting of parasitic elements and expressed using resistor (R), inductor (L) and capacitor (C) elements b) Y(f): Admittance, which is the inverse of Z(f)
The S-parameter, denoted as S(f), represents the ratio of reverse to forward voltage waves at the disturbance input of the Power Distribution Network (PDN) This parameter is essential for assessing the characteristics of radio frequency (RF) signal ports.
The conversion between the three types of parameters is described in Annex C The frequency validity range of the PDN is defined by the measurement conditions
The PDN can also be described as a circuit using a SPICE-like netlist
An integrated circuit (IC) can feature multiple identically designed pins with similar characteristics To simplify modeling, these pins can be categorized into families, including supply pins, digital input/output pins, analogue input/output pins, data/address buses, and communication buses.
Modeling the Power Distribution Network (PDN) of complex integrated circuits (ICs) as distinct blocks enhances representation and comprehension These blocks can be internally coupled, as seen in an IC that features both digital and analog sections with separate ground terminals, which may still be interconnected along with other coupled terminals.
IC Such coupling phenomena can be modelled using an Inter-Block Coupling (IBC) network
A detailed description of an IBC network is presented in 5.3
The PDN outlines the linear behavior of the device, excluding non-linear effects in the ICIM-CI macro-model Impedance measurements should be conducted under typical steady-state operating conditions The ICIM-CI model's PDN is designed to prevent the activation of internal protection devices, as their activation would introduce non-linearity not accounted for in the PDN Nonetheless, non-linear effects are inherently addressed in the IB, as detailed in section 5.4.
The Power Distribution Network (PDN) serves as a crucial filter for radio frequency (RF) disturbances, with resonances arising from parasitic capacitive and inductive elements Additionally, external components connected to the device's input and output pins can generate resonances that significantly impact device immunity The PDN has the ability to stop, pass, or amplify these disturbances, thereby influencing the overall immunity of the device.
The PDN is applicable under specific conditions, which encompass the power supply voltage range, the relevant frequency range, the temperature range, and the load conditions on the DI and/or DO pins.
The PDN impedance behavior is crucial for assessing the power delivered to the active components of devices, as illustrated by the IB model This transmitted power at the pin is associated with potential failures within the device.
IBC description
An Inter-Block Coupling (IBC) is a network of passive elements that facilitates coupling effects between various Power Distribution Network (PDN) blocks, forming an integral part of the PDN sub-model It features two or more internal terminals that connect to the internal terminals of PDN blocks, enabling the modeling of coupling phenomena such as interactions between different integrated circuit (IC) ground terminals, substrate losses, mutual inductances at the die level, and insulation between internal ground and power terminals An illustrative example of an IBC network is depicted in Figure 3.
NOTE ITVdd1, ITVss1, ITVdd2 and ITVss2 are internal nodes
Figure 3 – Example of an IBC network
In this example, the capacitors represent the dielectric properties, while the resistors illustrate the resistive characteristics of the substrate More intricate IBC networks can be utilized to model additional properties.
All specifications and conditions described for PDN in 5.2 are valid for IBC
A block-based structure, using IBC components, is illustrated in Figure 4 The model consists of different PDN block components and IBC components constituting the PDN sub-model
Figure 4 – ICIM-CI model representation with different blocks
IB description
The IB encompasses both in-band and out-of-band integrated circuit (IC) frequency responses through a secondary sub-model It outputs information via one or more output objects (OOs) that detail the IC's response to disturbing signals applied to one or more disturbance inputs (DIs) Key parameters included in the IB are frequency, transmitted power, and variations in the OOs Additionally, the IB accounts for inherent non-linearity that may lead to malfunctions.
OO is tested, IB data can be obtained using pass/fail or non pass/fail test criteria
In pass/fail tests, defects on the object of observation (OO) are evaluated against user-defined limits, leading to the creation of a specific IB sub-model for each susceptibility criterion.
In non pass/fail tests, the observed defects are not quantified as pass/fail (not tested against
The user-defined limits in the R model reflect the behavioral characteristics of the operational object (OO) based on transmitted power without predefined constraints As a result, the associated IB sub-model is designed to be more versatile, encompassing a wide range of practical applications Additionally, immunity criteria can be integrated into the OO by the user of the IC model during subsequent stages of model simulation or application.
The IB sub-model of the ICIM-CI model is influenced by the PDN and IBC, making its validity contingent upon specific conditions These conditions typically include the power supply voltage range, applicable frequency range, temperature range, load conditions affecting the DI and/or DO pin(s), and the immunity test criteria applied to the OO pin(s).
The frequency step-size and range for IB data must align with IEC 62132-1 standards Additionally, critical frequencies, including clock and system frequencies of RF devices, should be evaluated using finer frequency steps as mutually agreed upon by the procedure's users.
IB sub-model’s frequency range of validity is thus the same as that of the data (simulation or measurement) used for obtaining the IB
General
The ICIM-CI model data is structured in XML format, referred to as Conducted Immunity Markup Language (CIML) This data is divided into seven key sections: a) a Header with general information, b) definitions of IC's Lead, c) SPICE macro-model descriptions for PDN data, d) model validity conditions, e) details on PDN data, f) IBC data descriptions, and g) information on IB data.
The inheritance hierarchy is depicted in Figure 5
A CIML model definition comprises several key components, including the beginning of the model definition, the model header definition, DUT lead definitions, SPICE macro-models, model validity conditions, model PDN, model IBC, model IB, and the end of the model definition.
This exchange format uses eXtensible Markup Language (XML) 1.0 (Fourth Edition) to structure the information [1] XML is derived from the Standard Generalized Markup Language (SGML) (ISO 8879:1986)
The XML encoding rules outlined in Annex A guarantee that the XML (CIML) file is properly parsed by a Conducted Immunity Model (CIM) parser An illustrative example of a CIML file that adheres to the XML encoding format is provided in Annex D.
CIML structure
The typical ICIM-CI model shall be represented in CIML format as shown below:
The CIML format utilizes XML representation, adhering to the basic XML encoding rules outlined in Annex A Detailed information regarding CIML keywords and their usage can be found in Annex E.
The Header, Lead_definitions, Validity, Pdn and Ib sections are minimum and mandatory information of the ICIM-CI model The Macromodel and Ibc sections are optional.
Global keywords
Documentation, Notes, Unit sections are global keywords and can be placed anywhere in the file except within an element containing a value See E.4 for more information on their usage.
Header section
An independent Header section is utilized to enhance organization, rather than placing all header information directly under the element This approach allows for better grouping of related data within the XML structure.
The Header tag is essential for organizing components and enhancing the visual readability of model definitions It is recommended to include key header information such as the model version number, filename, and file version number Additional header contents can be customized to provide further relevant information.
An example Header section is shown below:
ExampleICIMCI_file.ciml
Valeo 1
DPI
A detailed list of valid keywords under the Header section is available in E.2.
Lead definitions
This section describes the various leads (or pins) of the IC under test Each lead in the
Lead_definitions section is made using the Lead tag, whose definition is shown in Table 1
Several Lead structures are listed one after another to form the Lead_definitions structure
Table 1 – Attributes of Lead keyword in the Lead_definitions section
Id: pin identity as a valid string (required)
Name : Name of the pin as designated in the datasheet (optional) Default = "None"
Mode: Mode in which the pin is used for ICIM-CI ("DI", "DO", "OO", " GND") See 5.1 Default="None"
Type: type of the lead ("internal" or "external") (optional) Default = "external"
In the Lead_definitions section, each Lead structure must include a required field, Id, which identifies the lead Additionally, leads can be defined by their Name, Mode, and Type If the Name field is not provided, it defaults to "None" The Mode field is also an important aspect of the lead's definition.
"None" under the following conditions:
• If Mode for a particular pin is absent
• If explicitly set as "None" since the respective pin is not DI, DO, OO or GND
The Type field is optional and is classified as "external" for DI, DO, OO, and GND mode pins Additionally, the lead type can be "internal" for connecting various blocks of the ICIM-CI PDN, as illustrated in Figure 4, with these pins defined using Mode="None." These leads are specifically designated for interfacing with the inter-block coupling network, detailed further in section 5.3 regarding IBC description.
When a pin operates in multiple modes, these modes are listed together in a single field, separated by commas It is important to note that no other characters can be used as delimiters.
The CIM parser indicates that the lead with Id="1" and name "T1" functions as both DI and OO By default, this lead is classified as an external terminal (Type="external").
Table 2 lists the compatibility between the Mode and Type fields of the Lead structure for correct CIML annotation by the CIM parser
Table 2 – Compatibility between the Mode and Type fields for correct CIML annotation
The different terminals described in 5.1 (see Figure 1) are represented in a compact format as shown below:
The code illustrates the structure of the ICIM-CI model as shown in Figure 1, with the pin identities ("Id") being selected arbitrarily These pin definitions serve as examples throughout this section of IEC 62433, unless stated otherwise.
SPICE macro-models
This section outlines the different SPICE macro-models formatted in netlist, which are referenced in the Pdn tag under the Netlist section as detailed in sections 6.8.3.4 and 6.8.3.5 Each macro-model is defined using the Subckt tag, as illustrated in Table 3 It is important to note that including this section in a CIML file is optional.
Name : Name of the SPICE macro-model (required)
Nodes: External Nodes connecting to the main circuit (required)
Kind : SPICE netlist format (optional) default: “SPICE3”
Data_files: SPICE macro-model defined in an external file (optional)
The Subckt keyword requires two essential fields: Name and Nodes The Name field must include letters and numbers as specified in A.2.5.4, while the Nodes field identifies the external nodes that connect the sub-circuit to the main circuit These external nodes are listed in sequence, separated by commas, and are strictly local to the SPICE macro-model definition Identification of these nodes can be done using either numbers or letters.
The optional attribute Kind tells the CIM parser that the defined sub-circuit (SPICE macro- model) follows a specific syntax CIML version 1 supports industry-standard SPICE like netlist syntaxes:
The Kind field defaults to generic "SPICE3" if absent An example Subckt element is shown below:
For compatibility across various SPICE types, the use of "0" as an external node is prohibited The Macromodels section is constructed by sequentially listing the different sub-circuit elements An example is provided to demonstrate the standard format of the Macromodels section.
Defined sub-circuits can be utilized within the Pdn and Ibc tags by using an identifier that begins with the character "X." These calls are made in the Netlist section and referenced through the Name field (refer to sections 6.8.3.4 and 6.8.3.5) It is essential that the number of nodes in the call line corresponds to the number specified in the Nodes attribute of the respective sub-circuit For instance, the previously defined "PDN_pin1" can be invoked accordingly.
If one or more sub-circuit models is defined in an external library file, then the file(s) is (are) referenced using the Data_files tag For example:
subckt_pin1.lib subckt_pin2.lib
A typical sub-circuit definition is shown in Figure 6
Figure 6 – Example of a netlist file defining a sub-circuit
To avoid ambiguity, the CIM parses only the data statements defined within the SPICE keywords: ".SUBCKT" and ".ENDS" These keywords are not case sensitive If multiple
".SUBCKT" sections are found, then they are parsed as independent sub-circuit elements
Since these definitions share the same namespace within the CIML format, every sub-circuit shall carry a unique name and shall conform to XML rules discussed in A.2.5.4.
Validity section
General
The Validity section is used to represent the conditions in which the ICIM-CI model is defined
This section is strictly informative to the user and independent of all other sections in the CIML file
Table 4 lists the various recognized keywords in the Validity section
Table 4 – Definition of the Validity section
Power_supply: Power supply range as a string (required)
Frequency_range: Frequency range as a string with units (required)
Temperature_range: Temperature range in which the model is extracted (required) To be specified with units
This definition is not exhaustive and is open for progress and improvement
The global keyword "Documentation" is used to specify the path to relevant IC documentation, including datasheets, test reports, and ICIM-CI extraction reports Multiple file paths can be listed sequentially, and if no paths are provided, the default value is "None." For further details on using the Documentation keyword, refer to section E.4.
The complete definition of the ICIM-CI model includes specific details outlined in the Notes section, which is represented as a valid string If no details are provided, it defaults to "None." For further information on the usage of the Notes keyword, refer to section E.4.
This section is mandatory and is defined directly under the CImodel root element For example:
[1MHz – 1GHz]
25Celsius
Only LIN network activated
Attribute definitions
The Power_supply attribute is used define the supply conditions for which ICIM-CI is valid
This attribute informs the user that the ICIM-CI model is extracted in the specified supply range
The value for this attribute should be easily understandable to ensure proper model usage It consists of a data string that may include valid text and/or numerical values with specified units, as detailed in section A.2.5.5.
A few examples of the Power_supply field are shown in Examples 1 to 3
EXAMPLE 1 The following syntax specifies that the model is defined for a supply voltage of 5 V
EXAMPLE 2 The following syntax specifies that the digital blocks of the model data are defined with a supply voltage of 5 V and the analogue blocks are defined for a supply voltage of 12 V
5V for digital blocks, 12V for analogue blocks
EXAMPLE 3 The following syntaxes specify that the model is defined for supply voltages between 2,5 V and 18 V
[2.5V-18V] or
between 2.5V and 18V
The Frequency_range attribute is used define the frequency range in which ICIM-CI is valid
The ICIM-CI model is designed for use within a specified frequency range, ensuring its applicability in that same range Its validity is determined by the overlapping frequency range of the Power Distribution Network (PDN) and the Input Buffer (IB).
The value for this attribute should be easily understandable to ensure proper model usage It consists of a data string that may include valid text and/or numerical values with units, as illustrated in Example 1 For a list of valid units, refer to section A.2.5.5.
EXAMPLE 1 The following syntaxes specify that the model is valid in the frequency range from 1 MHz to 1 GHz
[1MHz-1GHz] or
from 1MHz to 1GHz
The Temperature_range attribute specifies the temperature range for extracting ICIM-CI This model is valid within the overlapping temperature range of the Power Distribution Network (PDN) and the Integrated Circuit Interface (IB).
The value for this attribute should be easily understandable to ensure proper model usage It consists of a data string that may include valid text and/or numerical values with specified units, as detailed in section A.2.5.5.
Two examples are shown in Example 1 and Example 2
EXAMPLE 1 The following syntaxes specify that the model is valid in the temperature range between 20 °C and
[20Celsius-40Celsius] or
from 20Celsius to 40Celsius
EXAMPLE 2 The following syntax specifies that model is defined only at 298,15 K
PDN
General
The Pdn section of the ICIM-CI model contains the PDN data that describes the model The data shall be defined within the Pdn keyword as follows:
Different levels of PDN complexity can be identified, starting with the simplest configuration, which is the single-ended disturbance input A more advanced option is the differential disturbance input, while the most complex configuration involves a multi-port setup.
A PDN data is defined for a particular IC pin and thus the definition shall be done within a
The Lead tag is essential for structuring content, as illustrated in Figure 5, which depicts the structural hierarchy Multiple Lead elements can be organized sequentially within the Pdn section Additionally, Table 5 outlines the different recognized fields associated with the Lead keyword.
Table 5 – Definition of the Lead keyword for Pdn section
Id: pin identity as a valid string (required)
Ground_id : return pin identity as a valid string (required if Type=("S", "Z", "Y", else optional)
Blockname: PDN block name as a valid string
Type: PDN source parameter ("S", "Z", "Y", "Ckt")
Param_order: Order in which PDN parameters are defined
Format: Data format ("RI", "MA", "DB")
Meas_type: Method implemented for performing PDN measurements
Reference_impedance: Reference impedance used in performing PDN measurements
Use: Parameter that is to be specifically used
Netlist: PDN definition using standard netlist format
Unit_freq: Unit definition of the frequency terms
Unit_param: Unit of the PDN parameters
Power_level: Measurement power level during PDN extraction
Data_files: PDN source parameter defined in an external file (required if not List)
List: PDN parameter list (required if not Data_files)
The frequency range of the PDN information shall be specified in the Validity section under the Frequency_range tag
NOTE The frequency range of validity of the ICIM-CI model is the common frequency range of the PDN and IB.
Important information for the proper understanding and usage of the PDN can be optionally included in the Notes and Documentation tags This may encompass details like the IC operating mode, decoupling capacitors on supply lines, activated functions, grounding specifics, as well as datasheets and test reports.
Attribute definitions
The Lead Ids in the PDN definition must be previously defined in the Lead_definitions tag as outlined in section 6.5 Depending on whether the PDN is single-ended, differential, or multi-ended, multiple Ids may be specified together Both external and internal terminals are permissible, with additional details available in sections 6.8.4 and 6.8.5.
The Lead Ground_ids utilized in the PDN definition must be previously established in the Lead_definitions tag within GND mode, as outlined in section 6.5 This lead signifies the return signal path essential for defining the PDN.
The ground_id attribute is applicable only when network parameters are utilized to define the PDN with Type="S", "Z", or "Y" If the PDN is represented using a netlist with Type="Ckt", the CIM parser disregards the ground_id attribute For further details on the Type attribute, refer to section 6.8.2.4.
When used, only one unique Ground_id is permitted per Lead definition This is an optional field and is required if PDN is represented using network parameters
The Blockname field defines the name of the PDN block and is optional, serving to represent the PDN as a sub-block Illustrated in Figure 4, the block-based ICIM-CI macro-model highlights that this field is for informational purposes only, as the CIM parser does not interpret it.
The Type attribute is used to represent the type of the PDN data Valid types are:
• "Z": Z-parameter data These parameters are not normalized to the reference impedance
• "Y": Y-parameter data These parameters are not normalized to the reference impedance
• "Ckt": Circuit description using netlists
This field is optional When absent, the default value is "S"
The Param_order attribute informs the CIM parser about the data representation Its definition is unclear when the PDN is depicted as a circuit model, as outlined in sections 6.8.3.4 and 6.8.3.5 Specific strings are designated for indicating the parameter order.
• "Freq" and "Frequency": Frequency used for parameters’ definition
• "Sij": S-parameters, i and j are integers representing measurement ports/pins (example:
• "Zij": Z-parameters, i and j are integers representing measurement ports/pins (example:
• "Yij": Y-parameters, i and j are integers representing measurement ports/pins (example:
The different terms of Param_order shall be separated by a comma character (",")
This field is optional If absent, the default value is "Freq,S11"
The Format attribute decides the data format It is not defined if the PDN is represented as a circuit model as discussed in 6.8.3.4 and 6.8.3.5 Valid data formats are:
• "DB": Magnitude in decibel scale with phase angle in degrees
• "MA": Magnitude in linear scale with phase angle in degrees
This field is optional If absent, the default value is "RI"
The Meas_type attribute is essential for the CIM parser to calculate the impedance of a specific lead ("Id") when utilizing S-parameters This attribute varies in definition based on the type of Power Distribution Network (PDN), which can be single-ended, differential, or multi-ended For detailed information, refer to sections 6.8.4 and 6.8.5.
This field is defined only when Type="S" and is optional When absent, it defaults to "0"
The Reference_impedance attribute is used by the CIM parser in order to compute the impedance of the specific lead ("Id") when network parameters are used for PDN definition
This field is optional and applicable only when Type="S" If specified, it must include a numerical value with units, such as "50ohm", as outlined in A.2.5.3 If not provided, the default value is "50ohm".
The Use attribute tells the CIM parser to use one of the values in the Param_order attribute
When explicitly defined, the corresponding parameter is used as PDN If undefined, the first Sij or Zij or Yij term is used by default
The Netlist keyword defines the Power Distribution Network (PDN) as a SPICE netlist, illustrating the electrical connectivity of its elements according to SPICE specifications For a comprehensive understanding of the circuit model, refer to sections 6.8.3.4 and 6.8.3.5.
This field is required if Type="Ckt"
6.8.2.11 Unit_freq and Unit_param
The parameter units for frequency and data are specified under the Unit_freq and Unit_param tags In the absence of these specifications, Unit_freq defaults to "Hz" Additionally, Table 6 illustrates the default value of the Unit_param attribute based on the data type and format when it is not defined.
Table 6 – Valid data formats and their default units in the Pdn section
Data type Data format Default Unit_param values
The measurement power level used for PDN extraction (see 7.3.2) is specified in the
Power_level field For simplicity reasons, the power level along with units should be defined together as discussed in A.2.5.3
This is an optional field If absent, it defaults to "0dBm"
The Data_files tag distinguishes between inline and external data When PDN data is stored in an external file, the file's link must be included within the Data_files tag Inline data, on the other hand, is defined directly under the top-level Lead tag within a List tag if necessary Only files with the extensions listed in Table 7 are permitted.
Table 7 – Valid file extensions in the Pdn section
File extensions play a crucial role in identifying the type of data contained within a file Common file extensions include DAT for data files, CSV for comma-separated values, and TXT for text files Additionally, the extension SNP denotes Touchstone files, where 'n' represents an integer (1, 2, …) Other important extensions are CIR for circuit files (netlists), LIB for library files (netlists), and NET for netlist files Understanding these extensions is essential for effective file management and data organization.
The List tag is not defined if circuit model is used to describe the PDN Data_files tag is defined for network parameters (S or Z or Y) and netlist description
This is a required field; a unique List or Data_files element shall be used to define the PDN data of the specific lead.
PDN for a single-ended input or output
A single-ended input or output is linked to a single pin on the integrated circuit (IC), with the signal transmitted through one PCB track and the return signal track serving as the IC's electrical ground Different parts of the power distribution network (PDN) may have varying grounds, which can be interconnected either internally within the device or through external connections, potentially leading to imperfections It is crucial to consider these connections when extracting the PDN.
Figure 7 gives typical electrical schematics of single-ended input/output pins a) Input PDN electrical schematic b) Output PDN electrical schematic
R pkg Parasitic resistance of package
L pkg Parasitic inductance of package
C pkg Parasitic capacitance of package
C die Parasitic capacitance of die
Pin IC pin interface at the package level
Pad IC pin interface at the die level
Depending on the simulation tool used, the PDN could be represented with different network parameters such as S-, Z-, Y-parameters, or as a circuit/netlist using physical R, L and C elements
Figure 8 shows the impedance of the PDN represented by a one-port black-box
Figure 8 – PDN represented as a one-port black-box
Table 8 lists the valid fields of a Lead structure for a single-ended PDN definition and their usage
Table 8 – Valid fields of the Lead keyword for single-ended PDN
Id Identifier or pin number Required One unique Id previously defined in the Lead- definitions section
Ground_id Identifier or pin number of the return signal pin Required for Type="S" or
"Z" or "Y" One unique Id previously defined as GND in the Lead-definitions section
Blockname Name of the PDN block component Optional Valid string (see 6.8.1)
(S/Z/Y/Circuit) Optional Valid String: "S" (default) or "Z" or "Y" or "Ckt"
Param_order Order in which parameters are defined Optional Valid string (see 6.8.1)
Format Data format Optional "RI" (default) or "DB" or
Meas_type Method implemented for performing PDN measurements
Reference_impedance Reference impedance used in PDN measurements Optional Valid numerical value with units
Use Parameter that is to be specifically used Optional One of the values in
Param_order other than the Frequency term
Default: First S or Z or Y term
Netlist SPICE type netlist Required if Type="Ckt" Valid SPICE like data statements See 6.8.3.4 and 6.8.3.5
Unit_freq Frequency units Optional Valid units (see A.2.5.5)
Unit_param Parameter units Optional Valid units (see A.2.5.5)
Power_level Measurement power level Optional Valid numerical value with units (See A.2.5.5)
Data_files PDN source parameter defined in an external file Required if not List Valid for external netlist file or external network parameter file
List PDN data entries in the form of a list defined inline Required if not Data_files Valid numerical values with or without units in the specified order
The Id, Ground_id, Type, Param_order, and Format fields have been previously detailed in section 6.8.2 The CIM parser recognizes a pin's PDN definition as single-ended when the Id attribute holds a unique value, such as Id="1".
Meas_Type field is recognized only when the PDN is defined using S-parameters (Type= "S")
For all other types, this field is ignored CIML version 1 supports the following Meas_type values for single-ended PDN with S-parameters:
• "0" for standard or conventional measurement configuration (default)
• "1" when the DUT is in parallel to the measurement ports (shunt connection)
• "2" when the DUT is in series to the measurement ports (series connection)
The reference impedance used in PDN measurements is defined using the
Reference_impedance tag This field is recognized only when the PDN is defined using S- parameters (Type= "S")
The different measurement configurations and set-up for single-ended PDN extraction as defined in CISPR 17 are presented in 7.3 When absent, Meas_type defaults to "0" (conventional method)
Data can either be defined inline within the CIML file or can be defined using external data files for both network parameter and circuit (netlist) definition
When network parameters (S, Z, or Y) are specified for a single frequency, they can be directly defined within the Lead keyword However, if the Power Distribution Network (PDN) is defined for multiple frequencies, the data must be included within the List keyword Each different DI or DO lead, for which the PDN is defined, should be identified using the Id attribute, while the ground lead, designated with Mode="GND" in the Lead_definitions section, must be specified using the Ground_id attribute.
The frequency units are specified under the Unit_freq keyword, while data units are defined using the Unit_param keyword The measurement power level is indicated by the Power_level tag, and the reference impedance is set with the Reference_impedance tag For additional details on these attributes and their default values, refer to section 6.8.2.
The example demonstrates the single-ended Power Distribution Network (PDN) of lead "1," characterized by S-parameters obtained through the conventional Vector Network Analyzer (VNA) one-Port method, utilizing lead "7" as the ground (return signal pin) By default, the S-parameter used is "S11," and the PDN is represented as a block, with the Blockname designated as "Block_Pdn1."