Hi all, As we know, ibis model will be having two rising and two falling V-T tables. For differential buffers, (pad and padn) is it different? Do we need to have only one V-T table with Voltage source connected to VDDS? If anybody worked on differential buffer, please comment on this. Thanks in advance, Shantala On Tue, Mar 24, 2009 at 11:41 PM, Lynne D. Green <lgreen22@mindspring.com>wrote: > Hello, Shantala, > > IBIS captures only the behavior of the buffer. Since the magnitude of the > ground (and power) bounce depends on the board, it is not part of the IBIS > model. > > There have been discussions of ways to address model response to varying > Vcc-Gnd-Vee voltages. You might want to check the BIRDs and summit papers > on the IBIS web site for further information. > > Regards, > Lynne > > ------------------------------ > *From:* shantala hegde [mailto:h.shantala@gmail.com] > *Sent:* Tuesday, March 24, 2009 7:00 AM > *To:* Lynne D. Green > *Subject:* Re: [IBIS] V-T data query > > Thanks Lynne. > > I have one more doubt on rising/falling waveforms.I do not know much on > ground bounce.But, whats the main reason for capturing v-t data with voltage > source connected to ground in case of rising and vice-versa. > > I saw this rising/falling mismatch behaviour in pci buffers. > > Thanks in advance, > Shantala > > > > > > On Tue, Mar 24, 2009 at 9:56 AM, Lynne D. Green <lgreen22@mindspring.com>wrote: > >> Hello, Shantala, >> >> This turn on/off difference is probably designed to minimize crowbar >> current and power consumption. >> >> IBIS 4.x and 5.x require all V-t tables to have the same "reference" time >> (same clock edge). As Arpad noted, the same end time is not required in the >> tables. >> >> Lynne >> >> >> "IBIS training when you need it, where you need it." >> >> Dr. Lynne Green >> Green Streak Programs >> http://www.greenstreakprograms.com >> 425-788-0412 >> lgreen22@mindspring.com >> >> >> >> >> ------------------------------ >> *From:* owner-ibis@eda.org [mailto:owner-ibis@eda.org] *On Behalf Of *shantala >> hegde >> *Sent:* Monday, March 23, 2009 6:54 AM >> *To:* ibis-users@eda.org; ibis@eda.org >> *Subject:* [IBIS] V-T data query >> >> Hello all, >> >> I do have one question VT data. >> For example if I have an ibis model where [rising] data with voltage >> source connected to VDDS is a fast one.But the one which is connected to >> ground is slow rising. >> >> Say ,rising with vdds has 3ns and rising with ground connetced 10ns. >> >> Is this normal scenario or is it mandatory to have approximately same V-T >> end point for both rising/falling. >> >> Regards, >> Shantala >> >> >> -- >> This message has been scanned for viruses and >> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is >> >> believed to be clean. >> >> > -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.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 e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993Received on Mon Mar 30 06:40:25 2009
This archive was generated by hypermail 2.1.8 : Mon Mar 30 2009 - 06:41:21 PDT