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 |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just 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 written 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 1993 ----------------------------------------------------------------- |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 21 09:44:37 2005
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