Attached is BIRD95.3 with changes based on comments including those captured at the March 11, 2005 IBIS Meeting. The changes and justifications are discussed in the ANALYSIS PATH/DATA section. They include (1) changing the subparameters in BIRD95.2 to keywords for the effective impedance per buffer, (2) not supporting *_ECL models at this time, and (3) adding detail to the text based on some of the questions raised. BIRD95.3 will be discussed at the April 1st, 2005 IBIS Open Forum teleconference. Syed Huq Cisco Systems, Inc Acting Chair, EIA IBIS Open Forum ****************************************************************************** ****************************************************************************** BIRD ID#: 95.3 ISSUE TITLE: Power Integrity Analysis using IBIS REQUESTER: Syed Huq, Vinu Arumugham and Zhiping Yang, Cisco Systems, Inc.; Bob Ross, Teraspeed Consulting Group DATE SUBMITTED: December 13, 2004 DATE REVISED: January 28, 2005, March 8, 2005, March 29, 2005 DATE ACCEPTED BY IBIS OPEN FORUM: PENDING ****************************************************************************** ****************************************************************************** STATEMENT OF THE ISSUE: Power Integrity Analysis which includes Current switching profile of the Core as well as Simultaneous Switching Noise (SSN) of the Input/Output (I/O) stages of a buffer needs to be analyzed through IBIS. This BIRD proposes a modeling scheme to solve this. ****************************************************************************** STATEMENT OF THE RESOLVED SPECIFICATIONS: Power Integrity Analysis from a modeling perspective has been split into multiple tasks. Current into the power and ground rails are needed to give a more accurate analysis for ground and power bounce associated with simultaneous switching noise. Solving the Simultaneous Switching Noise (SSN) will be achieved through the use of I-T tables and [Z Equiv] keywords as part of this proposal. Five keywords and some other modifications are introduced: *** The [R Equiv], [L Equiv], [C Equiv] and [G Equiv] keywords are entered above the [Ramp] keyword in the document: |============================================================================== | Keywords: [R Equiv], [L Equiv], [C Equiv], [G Equiv] | Required: No | Description: Describes the impedance between the [Pullup Reference] and | [Pulldown Reference] in terms of a resistance, inductance, | capacitance in series and a parallel conductance. | Usage Rules: These keywords are positioned with the other keywords under the | [Model] keyword. | | For each of these keywords, the three columns hold the | typical, minimum, and maximum values. The three | entries must be placed on a single line and must be separated | by at least one white space. All three columns are required | under these subparameters. However, data is only required in | the typical column. If minimum and/or maximum values are not | available, the reserved word "NA" must be used, indicating that | the typical column entry will be used. | | These keywords are optional, but if any are missing, it takes | on a default value of zero. Thus [C Equiv], if missing, opens | the series path, and if [R Equiv] is missing, the resistance is | assumed zero. If [G Equiv] is missing, it is not included in | the model | | The keyword connections are defined with respect to reference | diagram in parallel to an I/O pin on the die on a per buffer | basis. The Power Pin is | the [Pullup Reference] and the Ground Pin is the [Pulldown | [Reference]. | | | | __________________________________ Power Pin | | [Pullup Reference] | ___________________|_______________________ | | | | | | ___________|______________ | | | ____|____ | | | | | | | | | | | | |[R Equiv]| | | Die | | | |_________| | | | | | ____|____ ____|____ ____|____ | | | | | | | | I/O | | | | |[L Equiv]| |[G Equiv]| | die |-------------- | | |_________| |_________| |_________| | | | ____|____ | | | | | | | | | | | | |[C Equiv]| | | | | | |_________| | | | | | |___________|______________| | | | | | | |___________________|_______________________| | | | |________________________________ Ground Pin | [Pulldown Reference] | | | These Keywords might not be effective for *_ECL technologies | because the [Pullup Reference] and [Pulldown Reference] are | connected to the same rail (which also can be Ground), and the | the most negative rail might not be specified. | | These keywords might not have any effect for the Model_type | settings of Input, Input_diff, Terminator, Series, and | Series_switch. These settings do not have a driver mode of | operation. | | Other Notes: The [R Equiv], [L Equiv], [C Equiv] and [G Equiv] keywords may | be used with, but do not require the [Composite Current] keyword | described later. Also, an example of a more detailed internal | network for these equivalent impedances is presented under the | [Composite Current] keyword. |------------------------------------------------------------------------------ | variable Typ Min Max | [R Equiv] 2.0m NA NA [L Equiv] 0.2n .3n .1n | Follow Process, Temperature [C Equiv] 2.0p 1.0p 1.3p | Voltage conditions with no [G Equiv] 2.0u NA NA | Ordering of values assumed | |============================================================================== *** The following keyword is positioned under the [Rising Waveform]/[Falling Waveform] keyword: Note, BIRD95.3 changes include substantial rewrite because of the conversion of the R_zvddq, L_zvddq, C_zvddq and G_zvddq subparameters into keywords. The BIRD95.2 text is retained at the end of BIRD95.3 for comparison since the rewritten text below does show the changes. |============================================================================== | Keywords: [Composite Current] | Required: No | Description: Describes the shape of the rising and falling edge | current waveforms from the power supply measured through | the power pin terminal. | Usage Rules: The [Composite Current] keyword is positioned under the | [Rising Waveform] (for rising waveform currents) and | [Falling Waveform] (for falling waveform currents. The keywords | are followed by | a table of current versus time rows (I-T) that | describe the shape of a current waveform. These I-T tables | inherit the fixture test load of the [Rising Waveform] | or [Falling Waveform] R/L/C/V_fixture and R/L/C_dut | subparameters. | | The [Composite Current] keyword is optional. It can be omitted, | or it can be positioned under a few, but not all of the rising | and falling waveform tables. | | The table itself | consists of one column of time points, then | three columns of current points in the standard typ, min, and | max format. The four entries must be placed on a single line and | must be separated by at least one white space. All four | columns are required. However, data is only required in the | typical column. If minimum or maximum data is not available, | use the reserved word "NA". The first value in the time column | need not be '0'. Time values must increase as one parses down | the table. The waveform table can contain a maximum of 1000 | data points. | | The I-T table data must be time-correlated with the V-T data | above. That is, the currents documented in the I-T table | correspond to the voltages in the V-T table at the identical | time points and for the given *_fixture load. | | The following diagram illustrates a typical configurating which | a [Rising Waveform] or [Falling Waveform is extracted. The | DUT die is modified to include the Power Pin and Ground Pin. | | | Power Pin | {Composite Current] | | | | | | PACKAGE | TEST FIXTURE | ____|____ | | | DUT | L_dut R_dut | L_fixture R_fixture | | die |---@@@@@--/\/\/\--o-----|--@@@@---o---/\/\/\--- V_fixture | |_________| | | | | | | | | | | | | | | | C_dut === | === C_fixture | | | | | | |_______________________|_____|_________|___ | Ground Pin | GND | | | The [Composite Current] direction is shown with respect to the | Power Pin. The new keywords are shown added to the DUT die. | These subparameters do not effect the [Rising Waveform] and | [Falling Waveform] table extractions, but give added equivalent | circuit detail for more accurate power pin current calculations. | | The [Composite Current] Keyword might not be effective for *_ECL | technologies | because the [Pullup Reference] and [Pulldown Reference] are | connected to the same rail (which also can be Ground}, and the | the most negative rail might not be specified. | | Other Notes: The internal networks for the DUT die 'Black Box' are shown | below to illustrate the effects that the equivalent circuit | are intended to describe. The Power Pin terminal is ahown as | VDDQ, and the Ground Pin terminal is shown as GND. | | | Black Box [Composite Current] | VDDQ | | o | __________________________________________________________________________| |__ || | | | || | | | || v | | || -------- -------- | | || | | | | | | || ____________________________________________|L_VDDQ|_|R_VDDQ|__| | || | | | | | | | | | | || | | | | | -------- -------- | || ----- | | | | | || | E | | / | | | || | S | ---------------- \ P_| --- PowerClamp | || | R | | Pre-Driver | / || / \ | || ----- | Circuit | \ ||_ --- | || | | powered by | | | | | || | | VDDQ | | | | | I_sig | || ----- ---------------- | | | | -------> | || | E | | o-----o--|----o---------------------------o || | S | | | | | | | Sig || | | L | | | | / | | | | || I_byp| ----- I_pre| |I_term| \ N_| v --- GNDClamp | || | | | | | / || I_cb / \ | || v | v | v \ ||_ --- | || ----- | | | | ------ ------- | || ----- C_p+b | | | | | | | | || |___________________|_________|_____|_______|___|L_GND|_|R_GND|__ | || | | | | | | || ------ ------- | | || | | || | | ||____________________________________________________________________________|__| | | | o | GND | | | Other elements in a more detailed typical (per buffer) model are: | | I_byp - Bypass current | I_pre - Pre-Driver current | I_cb - Crow-bar current | I_term - Termination current (optional) | L_VDDQ - On-die inductance of I/O Power | R_VDDQ - On-die resistance of I/O Power | L_GND - On-die inductance of Ground | R_GND - On-die resistance of Ground | C_p+b - Bypass + Parasitic Capacitance | ESR - Equivalent Series Resistance for on-die Decap | ESL - Equivalent Series Inductance for on-die Decap | | | The keywords [R Equiv], [L Equiv], [C Equiv] and [G Equiv] presented | earlier document an equivalent impedance of the internal Power pin | to Ground pin for each buffer as extracted at the terminals. The | [C Series], [Lc Series], [Rc Series] and [R Series] keywords along | with [Series Pin Mapping] could also be used to provide an equivalent | total impedance (versus a per buffer impedance) across the rails. In | the future, the ICM format might provide more accurate detail. | | The [C Equiv] value expressed on a per buffer basis captures the | effective bypass and parasitic for the internal structure of each | buffer. The extracted equivalent circuit would also capture the | C_comp* contribution attached to the rails. If the values are of | the same magnitude, then the C_comp* rail to rail contribution | should be subtracted from the the [C Equiv] values as a first order | adjustment. | | The Power Pin terminal in most cases is the [Pullup Reference], | or the default [Voltage Range] value. The [Pulldown Reference] is | usually the GND connection. | | If [POWER Clamp Reference] or [GND Clamp Reference] are different | than the [Pullup Reference] or [Pulldown Reference] voltages, | the model may not account for all of the currents. However, the | simulation of current transients should still be reasonable. | | The [Composite Current] can still be defined for Model_types without } the [Pullup] keywords (such as Open_drain) because the [Pullup | Reference] or [Voltage Range] are still required. Pre-driver and | other internal paths still exist. | | In most cases six [Composite Current] tables are recommended | for accurate modeling. The first four tables correspond to the | recommended fixture conditions for [Rising Waveform] and [Falling | Waveform] tables (normally 50 ohm loads to Vdd and GND). Two | additional waveforms for no load conditions (such as with an R_fixure | of 1.0 Megaohm) are useful. However, some EDA tools may use only | the first four waveforms. So these additional open load waveform | I-T tables should be in [Rising Waveform] and [Falling Waveform] | tables positioned after the other V-T tables to maintain the best | output response accuracy. These extra two tables do not apply | for any of the Open-drain and Open-source technologies. | | When the [Model] is configured differentially with the [Diff Pin] | keyword, the individual I-T currents for each [Model] is used as | an approximation. This summation may not be as accurate as the | the actual measured currents under actual operation. | | The [Composite Current] table can be derived from currents measured | at the GND node that have been transformed by combining with the | current at the output pin. | | The [Pin Mapping] keyword is used to document how buffers with | common voltage rails are connected. The effective impedances for | each buffer between the [Pullup Reference] and [Pulldown Reference] | are then combined to form the total effective impedance between | the voltage rails. | | The [Composite Current] keyword is not designed to accurately | document the effects of controlled switching buffers such as | those defined with [Submodel] or [Driver Schedule] keywords. | The additional currents for the specific controlled switching | fixture loads would be documented by the [Composite Curent] | values, but these additions might not describe the currents | for arbitrary load conditions because of control interactions. |------------------------------------------------------------------------------ | [Rising Waveform] R_fixture = 50.0 V_fixture = 0.0 | ... | ... | Rising Waveform table | ... [Composite Current] | | Time I(typ) I(min) I(max) 0 4.243E-05 NA NA 4.00E-11 4.244E-05 NA NA 8.00E-11 4.242E-05 NA NA 1.20E-10 4.265E-05 NA NA 1.60E-10 3.610E-05 NA NA 2.00E-10 3.903E-03 NA NA .. .. .. 3.80E-09 2.012E-02 NA NA 3.84E-09 2.012E-02 NA NA 3.88E-09 2.012E-02 NA NA 3.92E-09 2.012E-02 NA NA 3.96E-09 2.012E-02 NA NA 4.00E-09 2.012E-02 NA NA | [Falling Waveform] R_fixture = 50.0 V_fixture = 1.8 | ... | ... | Falling Waveform table | ... [Composite Current] | | Time I(typ) I(min) I(max) 0 4.302E-05 NA NA 4.00E-11 4.299E-05 NA NA 8.00E-11 4.304E-05 NA NA 1.20E-10 4.287E-05 NA NA 1.60E-10 4.782E-05 NA NA 2.00E-10 1.459E-04 NA NA .. .. .. 3.80E-09 4.933E-05 NA NA 3.84E-09 5.211E-05 NA NA 3.88E-09 5.490E-05 NA NA 3.92E-09 5.441E-05 NA NA 3.96E-09 4.842E-05 NA NA 4.00E-09 4.244E-05 NA NA | | ... etc. | |============================================================================== *** The following entries are made to the Tree diagram in Section 3a under the [Model] keywords as noted by the |*** lines: | | |-- [Lc Series] | | |-- [Rc Series] | | |-- [Series Current] | | |-- [Series MOSFET] Vds |*** Add these keywords | | |-- [R Equiv] | | |-- [L Equiv] | | |-- [C Equiv] | | |-- [G Equiv] |*** End of addition | | |-- [Ramp] dV/dt_r, dV/dt_f, | | |-- [Rising Waveform] R_fixture, V_fixture, | | | V_fixture_min, V_fixture_max, | | | C_fixture, L_fixture, R_dut, L_dut, | | | C_dut |*** Add this keywords | | | ----------------- | | | | | | | |-- [Composite Current] | | | |*** End of addition | | |-- [Falling Waveform] R_fixture, V_fixture, | | | V_fixture_min, V_fixture_max, | | | C_fixture, L_fixture, R_dut, L_dut, | | | C_dut |*** Add this keywords | | | ----------------- | | | | | | | |-- [Composite Current] | | | |*** End of addition | | |-- [Test Data] Test_data_type *, Driver_model, | | | Driver_model_inv, Test_load | | | ----------- *** The following change is made in Section 2, item 8) to add mho as a base unit as denoted in the |*** line: | 8) Valid scaling factors are: | T = tera k = kilo n = nano | G = giga m = milli p = pico | M = mega u = micro f = femto | When no scaling factors are specified, the appropriate base units are |*** assumed. (These are volts, amperes, ohms, mhos, farads, henries, and | seconds.) The parser looks at only one alphabetic character after a | numerical entry, therefore it is enough to use only the prefixes to | scale the parameters. However, for clarity, it is allowed to use full | abbreviations for the units, (e.g., pF, nH, mA, mOhm). In addition, | scientific notation IS allowed (e.g., 1.2345e-12). ****************************************************************************** ANALYSIS PATH/DATA THAT LED TO SPECIFICATION: Power Integrity Analysis has become a significat part of Signal Integrity Simulations and Analysis. Core voltages are going down with process enhancement and, I/O speeds are increasing, it is critical that high-speed applications solve Power Integrity issues on the die, package and PCBs combined. System failures can be traced to poor Power Integrity Designs. During the DesignCon2004 Power Integrity Panel, these issues were discussed. It was suggested to explore a solution through the IBIS commitee and hence this BIRD proposal. Several discussions were conducted(3/12/04,5/14/04,6/8/04,7/16/04,8/24/04) with the IBIS Futures Meetings. BIRD95.3: Based on comments and intent of BIRD95.2, the following changes were made: Subparameters for R_zvddq, L_zvddq, C_zvddq, and G_zvddq were changed to four keywords under [Model]: [R Equiv], [L Equiv], [C Equiv] and [G Equiv]. for the following reasons: (1) avoid repeating the same values for each occurance of [Composite Current] because there was never the intention to support different values, (2) to allow for typ-min-max values under the extraction conditions. The name change in keywords was made to conform better to the illustrative diagram components (ESR, ESL, etc) and to emphasize that these are overall equivalent values. A consequence of this syntactical change is that these keywords can be used whether or not [Composite Current] is defined. This is good because gate modulation control sometimes is sufficient in some devices. Several syntactical choices exist: (1) uses the [Series Pin Mapping] keyword and the already defined Series models, (2) write as subparameters under model similar to C_comp, (3) capture the group under new keyword (such as [Zvddq]) under [Model], but use a subparameter format under this like [Package] and R_pin, etc. (4) define as independent keywords such as [R Equiv], etc. like the [Rgnd], [Rpower] terimnator elements, (5) do nothing and rely on some future connection to hook up ICM with IBIS. Choice (1) has syntactical might not be available on a per buffer basis. Also, this requires a complete [Series Pin Mapping] pinout of all such connections along with the [Pin Mapping] keyword. Using the (2) subparameter method directly under [Model] is a syntactical departure from what we have traditionally done. Even some [Model Spec] subparameters are grouped under a keyword for grouping purpose. (Putting these additional impedances under [Model Spec] was also rejected because the describe electrical content, not specification information or specification test setups.) Positioning the subparameters under a keyword (such as [Zvvdq]) for grouping purposes is the preferred alternative and was almost used for BIRD95.3. While it has grouping advantages for content location purposes, and while it may follow the syntax similar to [Package] and its R_pin, L_pin, and C_pin subparameters, all electrical content under the [Model] keyword are described by keywords such as those for I-V tables, and terminators (e.g., [Rac], [Cac], [Rpower], [Rgnd]) or [TTpower], [TTgnd]. The choice for using the keyword format follows from these cases. The C_comp* subparameters remain the only exception. The other detail concerns more resolution on ECL/PECL support. The problem is that the negative reference supply is not required. The options are to simply list this as an unsupported exception at this time, or to add more requirements and conditions. The choice is changed to specify that it is not supported and leave its support to other BIRDs if there is a compelling industrial need. Some other changes per the discussion at the March 11, 2005 meeting: 1) _typ, _min, _max for the sub-params - Itzik Peleg Added with the four new keywords. 2) C_comp for Power and GND and it's relation to this BIRD - Arpad Muranyi Added by stating that C_comp* is assumed separate from [C Equiv]. 3) C_p+b, Is this Total or per I/O - John Angulo Stated per I/O 4) On-die cap for power rail, is this included or not - Michael Mirmak Assumed separate, if it exists and modeled by [C Series] 5) Make a statement that says, this is for a single buffer and not a complete component - John Angulo Assumed per single buffer by statements and positioning under [Model] 6) Z_VDDDQ subparams and placement under Model_type - Bob Ross/John Angulo Added statement that the new keywords might not be used for Input, Terminator, Series, Series Switch, Input_diff model_type. The positioning of [Composite Current] under the [Rising Waveform] and [Falling Waveform] keywords already constrain that it is used only where the waveform tables are used. The tree diagram and addition of mho as a base unit is added for completeness. Some Editorial changes and corrections are made. ****************************************************************************** ANY OTHER BACKGROUND INFORMATION: Other Power Integrity Related BIRDs are planned, but there may be future issues regarding exactly what is adopted to be discussed separately. Other than the already proposed BIRD97, BIRD95.3 has sufficient content for a complete solution at a lower level without these planned BIRDs: Linkage to a Core model will be achieved by BIRDXX (TBD). Linkage to an ICM model will be achieved by BIRDYY (TBD). Linkage to a Gate Modulation model will be achieved by BIRD97. This proposal is based on various past work done by many IBIS contributors and they are listed in no particular order. Links to ICEM are also listed: DesignCon2004 PDN Simulation panel proceedings material and slides: http://home.att.net/~istvan.novak/papers.html BIRD42.3: Modeling Current Waveforms C. Kumar, Bob Ross IBIS and ICEM interaction: B. Ross, Microelectronic Journal November 16, 2003 ICEM: ---- EMC for Component, Integrated circuits Electrical Model(ICEM) 93/XX/CDC, Project number 62014-3 Cookbook for Integrated Circuit model ICEM, Project number 62014-3 IBIS Summits: ------------- EMC model for prediction of parasitic emission, E. Sicard, March 2001 Electromagnetic Compatibility simulation of Printed Circuit Board, M. Christian, March 2001 ICEM - Proposal IEC62014-3, J.C.Perrin, March 2001 Advances of the ICEM model for Emission of Integrated Circuit, S. Calvet, January 2001 Adding On-Chip Capacitance in IBIS Format for SSO Simulation, R. Chen, January 2004 Simultaneous Switching Noise(SSN)Modeling, B. Unger January 2000 Crossbar-current out of CMOS-IBIS-Models, K. Koller & G .Bannert, March 2002 IC-Emit Comparing Simulated/Measured IC Emission Spectrum, E. Sicard & A. Soubeyran Februayr 2004 REVISION HISTORY CHANGES: Replace following BIRD95.1 lines: |*Power Integrity Analysis from a modeling perspective has been split into |*two tasks. |*1)Solving the Simultaneous Switching Noise (SSN) on the I/O level using current |* and future IBIS syntax. This will be achieved through IvsT tables. |*2)Solving the Core Current Switching profile using the ICEM (Integrated circuits |* Electrical Model specification, Project number 62014-3). This will be achieved |* by a call statement within IBIS calling an ICEM model. Using v4.1 IBIS syntax. replace: Current into the power and ground rails are needed to give a more accurate analysis for ground and power bounce associated with simultaneous switching noise. replace: | Keywords: [Series Composite Current] with: replace: | Description: Describes the shape of the rising and falling edge | current waveforms from the power supply measured through | R_VDD(see diagram). This includes Pre-driver, Crow-bar current, | on-die I_bypass and I_term(see diagram). replace: | Usage Rules: The [Series Composite Current] keyword is positioned under the replace: | | | -------- -------- (**) | | | | |<--- | _____________________________________________|L_VDDQ|_|R_VDDQ|__VDDQ | | | | | | | | | | | | | | | | -------- -------- | ----- | | | | | | E | | / | | | | S | ---------------- \ P_| --- PowerClamp | | R | | Pre-Driver | / || / \ | ----- | Circuit | \ ||__ --- | | | powered by | | | | | | | VDDQ | | | | | I_sig | ----- ---------------- | | | | -------> | | E | | o-----o--|----o---------- | | S | | | | | | | | | L | | | | / | | | |I_bypass| ----- I_pre| |I_term| \ N_| v --- GNDClamp | | | | | | / || I_cb / \ | v | v | v \ ||_ --- | ----- | | | | ------ ------- | ----- C_p+b | | | | | | | | | |___________________|_________|_____|_______|___|L_GND|_|R_GND|__GND | | | | | | ------ ------- | | I_bypass - Bypass current | I_pre - Pre-Driver current | I_cb - Crow-bar current | I_term - Termination current (optional) | L_VDDQ - On-die inductance of I/O Power | R_VDDQ - On-die resistance of I/O Power | L_GND - On-die inductance of Ground | R_GND - On-die resistance of Ground | C_p+b - Bypass + Parasitic Capacitance | ESR - Equivalent Series Resistance for on-die Decap | ESL - Equivalent Series Inductance for on-die Decap | | (**) - Current measure point The original BIRD95.2 [Composite Current] writeup is captured here for historical reference. |============================================================================== | Keywords: [Composite Current] | Required: No | Description: Describes the shape of the rising and falling edge | current waveforms from the power supply measured through | the power pin terminal illustrated more fully in the Usage | Rules. | Sub-params: R_zvddq, R L_zvddq, C_zvddq_typ, G_zvddq | Usage Rules: The [Composite Current] keyword is positioned under the | [Rising Waveform] (for rising waveform currents) and | [Falling Waveform] (for falling waveform currents. The keywords | are followed by optional on-die parasitic die subparameters and | then a table of current versus time rows (I-T) that | describe the shape of a current waveform. These I-T tables | inherit the fixture test load of the [Rising Waveform] | or [Falling Waveform] R/L/C/V_fixture and R/L/C_dut | subparameters. | | The [Composite Current] keyword is optional. It can be omitted, | or it can be positioned under a few, but not all of the rising | and falling waveform tables. | | The listed subparemeters, R_zvddq, L_zvddq, C_zvddq, and G_zvddq, | describe the impedance path between the power pin terminal and | ground (see Other Notes below). The first three subparameters | describe a series path of resistance, inductance and capacitance. | The forth subparameter describe a separate path in parallel to | the series path and also between the power pin terminal and | ground. | | These subparameters are optional, but if any are missing, they | take on a default value of zero. Thus C_zvddq, if missing, opens | the series path, and if R_zvddq is missing, the resistance is | assumed zero. If G_zvddq is missing, it is not included in the | model | | The I-T table follows these subparameters. The table itself | consists of one column of time points, then | three columns of current points in the standard typ, min, and | max format. The four entries must be placed on a single line and | must be separated by at least one white space. All four | columns are required. However, data is only required in the | typical column. If minimum or maximum data is not available, | use the reserved word "NA". The first value in the time column | need not be '0'. Time values must increase as one parses down | the table. The waveform table can contain a maximum of 1000 | data points. | | The following diagramss illustrate a typical configurating which | a [Rising Waveform] or [Falling Waveform is extracted. The | DUT die is modified to include the Power Pin and Ground Pin. | | | Power Pin | | | | | | | PACKAGE | TEST FIXTURE | ____|____ | | | DUT | L_dut R_dut | L_fixture R_fixture | | die |---@@@@@--/\/\/\--o-----|--@@@@---o---/\/\/\--- V_fixture | |_________| | | | | | | | | | | | | | | | C_dut === | === C_fixture | | | | | | |_______________________|_____|_________|___ | Ground Pin | GND | | | The [Composite Current] direction is shown with respect to the | Power Pin and the new subparameters are added to the DUT die. | These subparameters do not effect the [Rising Waveform and | [Falling Waveform] table extractions, but give added equivalant | circuit detail for more accurate power pin current calculations. | | ! [Composite Current] | <------ | __________________________________ Rower Pin | | | ___________________|_______________________ | | | | | | ___________|______________ | | | ____|____ | | | | | | | | | DUT | | | | R_zvddq | | | die | | | |_________| | | | | | ____|____ ____|____ ____|____ | | | | | | | | I/O | | | | | L_zvddq | | G_zvddq | | die |-------------- To L_dut | | |_________| |_________| |_________| | | | ____|____ | | | | | | | | | | | | | C_zvddq | | | | | | |_________| | | | | | |___________|______________| | | | | | | |___________________|_______________________| | | | |________________________________ Ground Pin | | | | Other Notes: The internal networks for the DUT die 'Black Box' are shown | below to illustrate the effects that the equivalent circuit | are intended to describe. The Power Pin terminal is ahown as | VDDQ, and the Ground Pin terminal is shown as GND. | | | VDDQ | Black Box (**) o | ___________________________________________________________________________||__ || || | || || | || v| | || -------- -------- | | || | | | | | | || ____________________________________________|L_VDDQ|_|R_VDDQ|__| | || | | | | | | | | | | || | | | | | -------- -------- | || ----- | | | | | || | E | | / | | | || | S | ---------------- \ P_| --- PowerClamp | || | R | | Pre-Driver | / || / \ | || ----- | Circuit | \ ||_ --- | || | | powered by | | | | | || | | VDDQ | | | | | I_sig | || ----- ---------------- | | | | -------> | || | E | | o-----o--|----o---------------------------o || | S | | | | | | | Sig || | | L | | | | / | | | | || I_byp| ----- I_pre| |I_term| \ N_| v --- GNDClamp | || | | | | | / || I_cb / \ | || v | v | v \ ||_ --- | || ----- | | | | ------ ------- | || ----- C_p+b | | | | | | | | || |___________________|_________|_____|_______|___|L_GND|_|R_GND|__ | || | | | | | | || ------ ------- | | || | | || | | ||____________________________________________________________________________|__| | | | o | GND | | (**) I-T - current through VDDQ terminal. | | Other elements typically in a more detailed model are | | I_byp - Bypass current | I_pre - Pre-Driver current | I_cb - Crow-bar current | I_term - Termination current (optional) | L_VDDQ - On-die inductance of I/O Power | R_VDDQ - On-die resistance of I/O Power | L_GND - On-die inductance of Ground | R_GND - On-die resistance of Ground | C_p+b - Bypass + Parasitic Capacitance | ESR - Equivalent Series Resistance for on-die Decap | ESL - Equivalent Series Inductance for on-die Decap | | | The subparameters R_zvddq, L_zvddq, C_zvddq and G_zvddq represent | and effective impedance of the internal Power pin to Ground pin | elements, as extracted from the terminals. In the future, the ICM | format might proivde more accurate detail, if needed. | NOTE: The Power Pin terminal in most cases is the [Pullup Reference], | or the default [Voltage Range] value. This [Pullup Reference] can | also be GND, as in some *_ECL technologies, and the Ground Pin is the | more negative reference. In such cases, the [GND Clamp Reference] | value should be defined. | | If [POWER Clamp Reference] or [GND Clamp Reference] are different | than the [Pullup Reference] or [Pulldown Reference] voltages, | the model may not account for all of the currents. However, the | simulatiion should still closely approximate the current transients. | | The [Composite Current] can still be defined for Model_types with } out the [Pullup] keywords (such as Open_drain) because the [Pullup | Reference] or [Voltage Range] are still required. Pre-driver and | other internal paths still exist. | | NOTE: In most cases six [Composite Current] tables are recommended | for accurate modeling. The first four tables correspond to the | recommended fixture conditions for [Rising Waveform] and [Falling | Waveform] tables (normally 50 ohm loads to Vdd and GND). Two | additional waveforms for no load conditions (such as with an R_fixure | of 1.0 megaohm are useful. However, some EDA tools may use only | the first four waveforms. So these additional open load waveform | I-T tables should be in [Rising Waveform] and [Falling Waveform] | tables positioned after the other V-T tables to maintain the best | output response accuracy. These extra two tables do not apply | for any of the Open-drain and Open-source technologies or for | ECL technologies. | | When the [Model] is configured differentially with the [Diff Pin] | keyword, the individual I-T currents for each [Model] is used as | an approximation. This summation may not be as accurate as the | the actual measured currents under actual operation. | | The [Composite Current] table can be derived from currents measured | at the GND node that have been transformed by combining with the | current at the output pin. | | The [Pin Mapping] keyword is used to docuemnt the voltage rails | of several buffers are combined. This combination includes the | effective impedances describe for each buffer | | The [Composite Current] keyword is not designed to accurately | document the effects of controlled switching buffers such as | those defined with [Submodel] or [Driver Schedule] keywords. |------------------------------------------------------------------------------ | [Rising Waveform] R_fixture = 50.0 V_fixture = 0.0 | ... | ... | Rising Waveform table | ... [Composite Current] R_zvddq = 2.0m L_zvddq = 0.2n C_zvddq = 2.0p G_zvddq = 2.0u | | Time I(typ) I(min) I(max) 0 4.243E-05 NA NA 4.00E-11 4.244E-05 NA NA 8.00E-11 4.242E-05 NA NA 1.20E-10 4.265E-05 NA NA 1.60E-10 3.610E-05 NA NA 2.00E-10 3.903E-03 NA NA .. .. .. 3.80E-09 2.012E-02 NA NA 3.84E-09 2.012E-02 NA NA 3.88E-09 2.012E-02 NA NA 3.92E-09 2.012E-02 NA NA 3.96E-09 2.012E-02 NA NA 4.00E-09 2.012E-02 NA NA | [Falling Waveform] R_fixture = 50.0 V_fixture = 1.8 | ... | ... | Falling Waveform table | ... [Composite Current] R_zvddq = 2.0m L_zvddq= 0.2n C_zvddq = 2.0p G_zvddq = 2.0u | | Time I(typ) I(min) I(max) 0 4.302E-05 NA NA 4.00E-11 4.299E-05 NA NA 8.00E-11 4.304E-05 NA NA 1.20E-10 4.287E-05 NA NA 1.60E-10 4.782E-05 NA NA 2.00E-10 1.459E-04 NA NA .. .. .. 3.80E-09 4.933E-05 NA NA 3.84E-09 5.211E-05 NA NA 3.88E-09 5.490E-05 NA NA 3.92E-09 5.441E-05 NA NA 3.96E-09 4.842E-05 NA NA 4.00E-09 4.244E-05 NA NA | | ... etc. | |------------------------------------------------------------------------------ ----------------------------------------------------------------- |For help or to subscribe/unsubscribe, email majordomo@eda.org |with the appropriate command message(s) in the body: | | help | subscribe ibis <optional e-mail address, if different> | subscribe ibis-users <optional e-mail address, if different> | unsubscribe ibis <optional e-mail address, if different> | unsubscribe ibis-users <optional e-mail address, if different> | |or email a request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993Received on Tue Mar 29 17:30:25 2005
This archive was generated by hypermail 2.1.8 : Tue Mar 29 2005 - 17:31:36 PST