Hi Akhilesh: The Specification may be slighly confusing in this area, but here are the the intended rules: 1. All four [* Reference] rails are required if [Voltage Range] missing. Otherwise [Voltage Range] is required. (This rule overreaches for rule statement simplicity reasons.) 2. [Voltage Range] only is acceptable (legacy reasons) 3. Your issue: [Voltage Range] with any or all of the [* Reference] rails are permitted - Each specified [* Reference] rail should be used. The [Voltage Range] and absolute 0 V GND should be considered a default value only if the [* Reference] is missing. Here is some of the text: |============================================================================= | Keyword: [Voltage Range] | Required: Yes, if [Pullup Reference], [Pulldown Reference], [POWER | Clamp Reference], and [GND Clamp Reference] are not present | Description: Defines the power supply voltage tolerance over which the | model is intended to operate. It also specifies the default | voltage rail to which the [Pullup] and [POWER Clamp] I-V data | is referenced. | Usage Rules: Provide actual voltages (not percentages) in the typ, min, max | format. "NA" is allowed for the min and max values only. | Other Notes: If the [Voltage Range] keyword is not present, then all four | of the keywords described below must be present: [Pullup | Reference], [Pulldown Reference], [POWER Clamp Reference], | and [GND Clamp Reference]. If the [Voltage Range] 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. |----------------------------------------------------------------------------- Comment - it is also legal to for [Voltage Range] and the other keywords to specify different voltages because no restriction is stated. |============================================================================= | Keyword: [Pullup Reference] | Required: Yes, if the [Voltage Range] keyword is not present | Description: Defines a voltage rail other than that defined by the [Voltage | Range] keyword as the reference voltage for the [Pullup] I-V | data. | Usage Rules: Provide actual voltages (not percentages) in the 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 typ, min, and max dV/dt_r values are derived. |----------------------------------------------------------------------------- Comment - not well worded, but the description should be interpreted as defining the voltage rail regardless of any (if it exists) [Voltage Range] entry. |============================================================================= | Keyword: [Pulldown Reference] | Required: Yes, if the [Voltage Range] keyword is not present | Description: Defines a power supply rail other than 0 V as the reference | voltage for the [Pulldown] I-V data. If this keyword is not | present, the voltage data points in the [Pulldown] I-V table | are referenced to 0 V. | Usage Rules: Provide actual voltages (not percentages) in the 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 typ, min, and max dV/dt_f values are derived. |----------------------------------------------------------------------------- Comment - Here the value is used (overriding the default reference of 0 V. Bob Akhilesh CHANDRA wrote: > Hello Bob, > > Yes, I think ELDO and HSPICE override voltage range while in HYPERLYNX > it does't, befor this I validate my models through ELDO and HSPICE now I > switch to HYPERLYNX and find out this problem . > In HYPERLYNX if keyword voltage range, power Clamp Reference and Pullup > Reference are presents then it take volatge range keywords for > simulation. In my view if optional keywords are present then it should > read from optional keywords. > > Regards > Akhilesh > > Bob Ross wrote: > >> Hello Akhilesh: >> >> In some tool, the [Pullup Reference] and/or the [Power Clamp Reference] >> will override the [Voltage Range]. >> >> Bob >> >> Tom Dagostino wrote: >> >>> IBIS voltages only are concerned with the voltage applied to the >>> output or >>> input stage (that may be changing with some of the new birds being >>> discussed). They define which rail, voltage, the currents will flow >>> into or >>> out of. For an output the Voltage Range key word will tell the >>> simulator >>> what supply voltage the output's pullup will supply current from and >>> what >>> supply voltage the power clamp if present will dump current into. If >>> there >>> is a Pullup Reference and a Powerclamp Reference stated in the model >>> then >>> first, they describe the power supply that sources current for the >>> pullup >>> and power supply that sinks current for the clamp. In this case the >>> Powerclamp Reference and be different than the Pullup Reference. A good >>> example of this would be a 3.3V output buffer (Pullup Reference) that >>> is 5 >>> Volt compatible with a Powerclamp Reference of 5.0 Volts. >>> >>> It is unlikely that your example would ever occur. If your Pullup >>> Reference >>> is 2.5V your Voltage Range, the operating is not 1.2 Volts. The core >>> supply >>> voltage should not be in the model, it is not sinking or sourcing >>> currents >>> in the input or output stage. >>> >>> Tom Dagostino >>> Teraspeed Labs >>> 13610 SW Harness Lane >>> Beaverton, OR 97008 >>> 503-430-1065 >>> http://www.teraspeed.com >>> tom@teraspeed.com >>> >>> Teraspeed Consulting Group LLC >>> 121 North River Drive >>> Narragansett, RI 02882 >>> 401-284-1827 >>> >>> Teraspeed is the registered service mark of >>> Teraspeed Consulting Group LLC >>> >>> -----Original Message----- >>> From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org]On >>> Behalf Of Akhilesh CHANDRA >>> Sent: Thursday, April 21, 2005 6:56 AM >>> To: ibis; ibis-users >>> Cc: Akhilesh CHANDRA >>> Subject: [IBIS-Users] difference between [Pullup Reference] and [Voltage >>> Range] >> >> >> >>> >>>> >>> Hello Friends, >>> >>> As I read in IBIS standard >>> >>> Voltage Range----Defines the power supply voltage tolerance over which >>> the model is intended to operate. >>> Pullup Reference--Defines a voltage rail other than that defined by the >>> [Voltage Range] keyword as the reference voltage for the [Pullup] I-V >>> data. >>> My buffer have dual supply VDD and VDDE2V5. VDD is the core side >>> supply and VDDE2V5 voltage at the pad as well as voltage at the pullup >>> and power clam diode. >>> >>> I wnat to know how this information is use in the simulation. >>> When pullup information is present then it's overwrite voltag >>> information? >>> >>> I have given >>> [Voltage Range] 1.2 1.1 1.3 >>> [Pullup Reference] 2.5 2.2 2.7 >>> >>> Which information is used in the simulation. >>> >>> Regards >>> Akhilesh >>> >> >>> >>> >> > > > -- Bob Ross Teraspeed Consulting Group LLC Teraspeed Labs 121 North River Drive 13610 SW Harness Lane Narragansett, RI 02882 Beaverton, OR 97008 401-284-1827 503-430-1065 http://www.teraspeed.com 503-246-8048 Direct bob@teraspeed.com Teraspeed is a registered service mark of Teraspeed Consulting Group LLC ----------------------------------------------------------------- |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 Thu Apr 28 10:06:08 2005
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