|* are retained for backward compatibility. Model_types with
|* "open_source" specify that the output has an OPEN side (the
|* [Pulldown keyword is not used or I = 0mA for all voltages
|* specified) AND the output SOURCES current. Model_types with
|* "_ECL" specify that the model represents and ECL type logic
|* which follows different conventions for the [Pulldown] keyword.
|*
| Note that C_comp defines the silicon die capacitance. This |
| value should not include the capacitance of the package. |
| |
|------------------------------------------------------------------------------|
[Model] model_name
|*
|* BIRD7.2 modification
Model_type Input, Output, I/O, 3-state, Open_drain, I/O_open_drain,
Open_sink, I/O_open_sink, Open_source, I/O_open_source,
Input_ECL, Output_ECL, I/O_ECL | List one only
|*
Polarity Non-Inverting, Inverting | List one only, if any
Enable Active-High, Active-Low | List one only, if any
| Signals RAS, CAS, A(0-64), D(0-128),... | Local list, if desired
Vinl = 0.8V | input logic "low" DC voltage, if any
Vinh = 2.0V | input logic "high" DC voltage, if any
| variable typ min max
C_comp 12.0pF 10.0pF 15.0pF
|==============================================================================|
| Keyword: [Voltage range] |
| Required: Yes |
| Description: Used to define the power supply voltage tolerance over which |
| the model is intended to operate. |
| Usage Rules: Actual voltages (not percentages) are to be presented in the |
| usual typ, min, max format. "NA" is allowed for the min and |
| values only. |
| Other Notes: [Voltage range] also describes the voltage range over which |
| the various V/I curves and ramp rates were derived. |
|------------------------------------------------------------------------------|
| variable typ min max
[Voltage range] 5.0V 4.5V 5.5V
|******************************************************************************
|* BIRD3 replacement of [Voltage range] text above for VERSION 1.1X
|*==========================================================================
|* Keyword: [Voltage range]
|* Required: Yes, if [Pullup reference], [Pulldown reference],
|* [Power_clamp reference], and [GND_clamp reference] are not
|* present
|*Description: Used to define the power supply voltage tolerance over which
|* the the model is intended to operate. It also specifies the
|* default voltage rail the pullup and POWER_clamp V/I data is
|* referenced to.
|*Usage Rules: Actual voltages (not percentages) are to be presented in the
|* usual typ, min, max format. "NA" is allowed for the min and
|* max values only.
|*---------------------------------------------------------------------------
|* variable typ min max
[Voltage range] 5.0v 4.5v 5.5v
|*===========================================================================
|* Keyword: [Pullup reference]
|* Required: Yes, if the [Voltage range] keyword is not present.
|*Description: Used to define a voltage rail other than that defined by
|* the [Voltage range] keyword as the reference voltage
|* for the pullup V/I data.
|*Usage Rules: Actual voltages (not percentages) are to be presented in the
|* usual typ, min, max format. "NA" is allowed for the min and
|* max values only.
|*Other Notes: This keyword, if present, also defines the voltage range over
|* which the min and max dV/dt_r values are derived.
|*---------------------------------------------------------------------------
|* variable typ min max
[Pullup reference] 5.0V 4.5V 5.5V
|*===========================================================================
|* Keyword: [Pulldown reference]
|* Required: Yes, if the [Voltage range] keyword is not present.
|*Description: Used to define a power supply rail other than 0v as the
|* reference voltage for the pulldown V/I data. If this keyword
|* is not present the voltage data points in the pulldown V/I table
|* are referenced to 0v.
|*Usage Rules: Actual voltages (not percentages) are to be presented in the
|* usual typ, min, max format. "NA" is allowed for the min and
|* max values only.
|*Other Notes: This keyword, if present, also defines the voltage range over
|* which the min and max dV/dt_f values are derived.
|*---------------------------------------------------------------------------
|* variable typ min max
[Pulldown reference] 0V 0V 0V
|* Keyword: [POWER_clamp reference]
|* Required: Yes, if the [Voltage range] keyword is not present.
|*Description: Used to define a voltage rail other than that defined by
|* the [Voltage range] keyword as the reference voltage
|* for the POWER_clamp V/I data.
|*Usage Rules: Actual voltages (not percentages) are to be presented in the
|* usual typ, min, max format. "NA" is allowed for the min and
|* max values only.
|*Other Notes: Refer the "NOTES ON SPECIFYING POWER SUPPLIES" section below.
|*---------------------------------------------------------------------------
|* variable typ min max
[POWER_clamp reference] 5.0V 4.5V 5.5V
|*===========================================================================
|* Keyword: [GND_clamp reference]
|* Required: Yes, if the [Voltage range] keyword is not present.
|*Description: Used to define a power supply rail other than 0v as the
|* reference voltage for the GND_clamp V/I data. If this keyword
|* is not present the voltage data points in the GND_clamp V/I table
|* are referenced to 0v.
|*Usage Rules: Actual voltages (not percentages) are to be presented in the
|* usual typ, min, max format. "NA" is allowed for the min and
|* max values only.
|*Other Notes: Refer to the "NOTES ON SPECIFYING POWER SUPPLIES" section below.
|*---------------------------------------------------------------------------
|* variable typ min max
[GND_clamp reference] 0V 0V 0V
|*============================================================================
|* NOTES ON SPECIFYING POWER SUPPLIES
|* It is the intention that standard TTL and CMOS devices be specified
|* using only the [Voltage range] keyword. However, in cases where
|* the output characteristics of a device depend on more than a single
|* supply and ground, or a pullup, pulldown or clamp structure is referenced
|* to something other than the default supplys, the additional 'reference'
|* keywords are to be used.
|* If the [Voltage range] keyword is not present then all four of the
|* other keywords must be present. If the [Voltage range] keyword is
|* present the other keywords are optional and may or may not be used as
|* required. It is legal (although redundant) for an optional keyword to
|* specify the same voltage as specified by the [Voltage range] keyword.
|******************************************************************************
|==============================================================================|
| Keywords: [Pulldown], [Pullup], [GND_clamp], [POWER_clamp] |
| Required: Yes, if they exist in the device |
| Description: The data points under these keywords define the V/I curves of |
| the pulldown and pullup structures of an output buffer and the |
| V/I curves of the clamping diodes connected to the GND and the |
| POWER pins, respectively. |
| Usage Rules: In each of these sections the first column contains the |
| voltage value, and the three remaining columns hold the |
| typical, minimum, and maximum current values. The four |
| entries, Voltage, I(typ), I(min), and I(max) must be placed on |
| a single line and must be separated by at least one white |
| space or tab character. |
| All four columns are required under these keywords, however |
| data is only required in the typical column. If minimum |
| and/or maximum current values are not available, the reserved |
| word "NA" must be used. "NA" can be used for currents in the |
| typical column, but numeric values MUST be specified for the |
| first and last voltage points on any V/I curve. Each V/I |
| curve must have at least 2, but not more than 100, voltage |
| points. |
| Other Notes: It should be noted that the V/I curve of the [Pullup] and the |
| [POWER_clamp] structures are 'Vcc relative', meaning that the |
| voltage values are referenced to the Vcc pin. The voltages in |
| the data tables are derived from the equation: |
| Vtable = Vcc - Voutput |
| Therefore, for a 5V component, -5 V in the table actually |
| means 5 V above Vcc, which is +10 V with respect to ground; |
| and 10 V means 10 V below Vcc, which is -5 V with respect to |
| ground. Vcc-relative data is necessary to model a pullup |
| structure properly, since the output current of a pullup |
| structure depends on the voltage between the output and Vcc |
| pins and not the voltage between the output and ground pins. |
| Note that the [GND_clamp] V/I curve can include quiescent |
| input currents, or the currents of a 3-stated output if so |
| desired. |
|******************************************************************************
|* BIRD4 ADDITION FOR VERSION 1.1X
|* When tabulating data for ECL devices, the data in the pulldown table
|* is measured with the output in the 'logic low' state. In other words,
|* the data in the table represents the V-I characteristics of the
|* output when the output is at the most negative of its two logic
|* levels. Likewise, the data in the pullup table is measured with the
|* output in the 'logic one' state and represents the V-I characteristics
|* when the output is at the most positive logic level. Note that in BOTH
|* these cases the data is referenced to the VCC supply voltage, using
|* the equation Vtable = Vcc - Voutput.
|******************************************************************************
|------------------------------------------------------------------------------|
[Pulldown]
| Voltage I(typ) I(min) I(max)
|
-5.0V -40.0m -34.0m -45.0m
-4.0V -39.0m -33.0m -43.0m
| .
| .
0.0V 0.0m 0.0m 0.0m
| .
| .
5.0V 40.0m 34.0m 45.0m
10.0V 45.0m 40.0m 49.0m
|
[Pullup]
|
| Voltage I(typ) I(min) I(max)
|
-5.0V 32.0m 30.0m 35.0m
-4.0V 31.0m 29.0m 33.0m
| .
| .
0.0V 0.0m 0.0m 0.0m
| .
| .
5.0V -32.0m -30.0m -35.0m
10.0V -38.0m -35.0m -40.0m
|
[GND_clamp]
|
| Voltage I(typ) I(min) I(max)
|
-5.0V -3900.0m -3800.0m -4000.0m
-0.7V -80.0m -75.0m -85.0m
-0.6V -22.0m -20.0m -25.0m
-0.5V -2.4m -2.0m -2.9m
-0.4V 0.0m 0.0m 0.0m
5.0V 0.0m 0.0m 0.0m
|
[POWER_clamp]
|
| Voltage I(typ) I(min) I(max)
|
-5.0V 4450.0m NA NA
-0.7V 95.0m NA NA
-0.6V 23.0m NA NA
-0.5V 2.4m NA NA
-0.4V 0.0m NA NA
0.0V 0.0m NA NA
|==============================================================================|
| Keyword: [Ramp] |
| Required: Yes, except for inputs |
| Description: Used to define the rise and fall times of a buffer. |
| Sub-Params: dV/dt_r, dV/dt_f |
| Usage Rules: These parameters describe an ideal slope and can be expressed |
| as a ratio of any reasonable voltage and time values as shown |
| in the examples. The [Ramp] values are allowed to use "NA" |
| for the min and max values only. |
|------------------------------------------------------------------------------|
[Ramp]
| variable typ min max
dV/dt_r 4.2/1.8n 3.5/2.5n 5.0/1.1n
dV/dt_f 2.5/1.5n 2.0/2.3n 3.0/0.8n
|==============================================================================|
| Keyword: [End] |
| Required: Yes |
| Description: Used to define the end of the .ibs file. |
|------------------------------------------------------------------------------|
[End]
|==============================================================================|
| |
| NOTES ON DATA DERIVATION METHOD |
| |
| This section explains how data values are derived. The intention here is to |
| avoid over-guardbanding, enabling simulation results that are meaningful and |
| useful. This is accomplished by having each silicon vendor base their data |
| on typical process data, and then derate by voltage and temperature, and a |
| proprietary "X%" factor. This methodology also has the nice feature that |
| the data can be derived either from vendor-proprietary silicon models, or |
| typical device measurement over temperature/voltage. |
| |
| 1) V/I curves for CMOS devices: |
| typ = nominal voltage, 50 degrees C, typical process |
| min = low voltage tol, 100 degrees C, typical process, minus "X%" |
| max = hi voltage tol, 0 degrees C, typical process, plus "X%" |
| |
| V/I curves for bipolar devices: |
| typ = nominal voltage, 50 degrees C, typical process |
| min = low voltage tol, 0 degrees C, typical process, minus "X%" |
| max = hi voltage tol, 100 degrees C, typical process, plus "X%" |
| |
| where X% should be statistically determined by the silicon vendor |
| based on numerous fab lots, test chips, process controls, ... The |
| value of X need not be published in the IBIS file, and may decrease |
| over time as data on the I/O buffers and silicon process increases. |
| Temperatures are junction temperatures. |
| |
| 2) Voltage Ranges: |
| Points for each curve must span the voltages listed below: |
| |
| Curve Low Voltage High Voltage |
| ----------- ----------- ------------ |
| [Pulldown] GND - POWER POWER + POWER |
| [Pullup] GND - POWER POWER + POWER |
| [GND_clamp] GND - POWER GND + POWER |
| [POWER_clamp] POWER POWER + POWER |
| |
| For example, a device with a 5 V power supply voltage should be |
| characterized between (0 - 5) = -5 V and (5 + 5) = 10 V; |
| and a device with a 3.3 V power supply should be characterized |
| between (0 - 3.3) = -3.3 V and (3.3 + 3.3) = 6.6 V for the |
| pulldown curve. |
|
|******************************************************************************
|* BIRD4 ADDITION FOR VERSION 1.1X
|* When tabulating output data for ECL type devices, the voltage points
|* must span the range of VCC to VCC - 2.2V. This range applies to both the
|* pullup and pulldown tables. Note that this range applies ONLY when
|* characterizing an ECL output.
|******************************************************************************
| |
| 3) Ramp Rates: |
| The ramp rates (listed in AC characteristics below) should be |
| derived by: |
| 1. Start with silicon model, remove all packaging. |
| 2. Attach 50 Ohm resistor to GND to derive rising edge ramp. |
| 3. Attach 50 Ohm resistor to POWER to derive falling edge ramp. |
| 4. Due to the resistor, output swings will not make a full |
| transition as expected. However the pertinent data can still |
| be collected as follows: |
| a) determine the 20% to 80% voltages of the 50 Ohm swing |
| b) measure this voltage change as "dv" |
| c) measure the amount of time required to make this swing "dt" |
| 5. Post the value as a ratio "dv/dt", the simulation tool vendor |
| will extrapolate this value to span the required voltage swing |
| range in the final model. |
| 6. Typ, Min, and Max must all be posted, and are derived at the |
| same extremes as the V/I curves, which are: |
| |
| Ramp times for CMOS devices: |
| typ = nominal voltage, 50 degrees C, typical process |
| min = low voltage tol, 100 degrees C, typical process, minus "Y%" |
| max = hi voltage tol, 0 degrees C, typical process, plus "Y%" |
| |
| Ramp times for bipolar devices: |
| To be determined by manufacturer. |
| |
| Note that the derate factor, "Y%", may be different than that used |
| for the V/I curve data. This factor is similar to the X% factor |
| described above. As in the case of V/I curves, temperatures are |
| junction temperatures here also. |
| |
| 7. The rise time of an open-drain device must be measured into |
| a 50 Ohm pullup resistor tied to the power pin. |
| |
|******************************************************************************
|* BIRD7.2 REPLACEMENT OF 3) FOR VERSION 1.1X
|* NOTE, Items 3. and 7. above deleted, Items 4. thru 6. renumbered 3. thru 5.
|*
|* 3) Ramp Rates:
|* The ramp rates (listed in AC characteristics below) should be derived
|* as follows:
|*
|* 1. Start with the silicon model, remove all packaging.
|*
|* 2. If: The Model_type is one of the following: Output, I/O, or
|* 3-state (not open or ECL types);
|* Then: Attach a 50 ohm resistor to GND to derive the rising edge
|* ramp. Attach a 50 ohm resistor to POWER to derive the
|* falling edge ramp.
|*
|* If: the Model_type is Output_ECL or I/O_ECL;
|* Then: Attach a 50 ohm resistor to the termination voltage
|* (Vterm = VCC - 2v). Use this load to derive both the
|* rising and falling edges.
|*
|* If: The Model_type is either an open_sink type or open_drain type;
|* Then: Attach either a 50 ohm resistor or the vendor suggested
|* termination resistance to either POWER or the vendor suggested
|* termination voltage. Use this load to derive both the rising
|* and falling edges.
|*
|* If: The Model_type is an open_source type;
|* Then: Attach either a 50 ohm resistor or the vendor suggested
|* termination resistance to either GND or the vendor suggested
|* termination voltage. Use this load to derive both the rising
|* and falling edges.
|*
|* 3. Due to the resistor, output swings will not make a full
|* transition as expected. However the pertinent data can still
|* be collected as follows:
|* a) determine the 20% to 80% voltages of the 50 Ohm swing
|* b) measure this voltage change as "dv"
|* c) measure the amount of time required to make this swing "dt"
|* 4. Post the value as a ratio "dv/dt", the simulation tool vendor
|* will extrapolate this value to span the required voltage swing
|* range in the final model.
|* 5. Typ, Min, and Max must all be posted, and are derived at the
|* same extremes as the V/I curves, which are:
|*
|* Ramp times for CMOS devices:
|* typ = nominal voltage, 50 degrees C, typical process
|* min = low voltage tol, 100 degrees C, typical process, minus "Y%"
|* max = hi voltage tol, 0 degrees C, typical process, plus "Y%"
|*
|* Ramp times for bipolar devices:
|* To be determined by manufacturer.
|*
|* Note that the derate factor, "Y%", may be different than that used
|* for the V/I curve data. This factor is similar to the X% factor
|* described above. As in the case of V/I curves, temperatures are
|* junction temperatures here also.
|******************************************************************************
|
| It is expected that this data will be created from silicon vendor |
| proprietary silicon-level models, and later correlated with actual device |
| measurement. |
|==============================================================================|
|******************************************************************************|
| ADDITIONAL NOTES FOR IBIS EXTENSIONS (BIRDS) |
|******************************************************************************|
*******************************************************************************
NOTES ON BIRD3
Received on Sun Feb 20 19:00:04 1994
This archive was generated by hypermail 2.1.8 : Fri Jun 03 2011 - 09:52:28 PDT