Subject: Re: [IBIS-Users] LVDS RECEIVER TERMINATION Question
From: Adam.Tambone@fairchildsemi.com
Date: Tue Jul 23 2002 - 07:32:38 PDT
Hello Peter,
No need for for an apology, you understood me correctly and answered my
question.
OK, so I think we are on the same page regarding a dynamic clamp accounting
for the effect of the internal termination. I think the the LVDS driver
must be included for the I-V measurements of the LVDS receiver. In other
words, let the driver perform the DC sweep on the inputs : )
Adam
|---------+--------------------------->
| | Peter LaFlamme |
| | <plaflamm@amcc.c|
| | om> |
| | |
| | 07/23/02 10:12 |
| | AM |
| | |
|---------+--------------------------->
>-------------------------------------------------------------------------------------------------------------------------------|
| |
| To: Adam Tambone/SouthPortland/Fairchild@Fairchild |
| cc: ibis-users@eda.org |
| Subject: Re: [IBIS-Users] LVDS RECEIVER TERMINATION Question |
>-------------------------------------------------------------------------------------------------------------------------------|
Hi Adam,
I am sorry. I guess I misunderstood what your question was. I believe that
some people use a "dynamic clamp" to implement the resistor termination. I
am unsure how valid this approach is, based on some of the models that I
have tested.
Regards,
Peter
-- Peter LaFlammeApplied Micro Circuits Corp. System Applications Engineer 200 Minuteman Rd, 3rd Floor Andover, MA 01810
978-247-8470 phone 978-623-0055 Fax
Adam.Tambone@fairchildsemi.com wrote: > > Hello Peter, > > Yes, I am wondering if there is a method where the pwr/gnd clamping curve > can also account for the termination since it appears that simulation tools > do not recognize the series model. > > Adam > > |---------+---------------------------> > | | Peter LaFlamme | > | | <plaflamm@amcc.c| > | | om> | > | | Sent by: | > | | owner-ibis-users| > | | @eda.org | > | | | > | | | > | | 07/23/02 09:46 | > | | AM | > | | | > |---------+---------------------------> > > -------------------------------------------------------------------------------------------------------------------------------|
> | | > | To: Adam Tambone/SouthPortland/Fairchild@Fairchild | > | cc: ibis-users@eda.org | > | Subject: Re: [IBIS-Users] LVDS RECEIVER TERMINATION Question | > > -------------------------------------------------------------------------------------------------------------------------------|
> > Hi Adam, > Thanks for the interest and response. In regards to your question, one of > the inputs can be left floating to get the pwr/gnd clamp info. The other > part of the model will take care of the resistor termination and its > variation over process. > > Regards, > Peter > > -- > Peter LaFlamme > > Applied Micro Circuits Corp. > System Applications Engineer > 200 Minuteman Rd, 3rd Floor > Andover, MA 01810 > > 978-247-8470 phone > 978-623-0055 Fax > > Adam.Tambone@fairchildsemi.com wrote: > > > > Hello Peter, > > > > I have an additional question regarding what you have described below. > If > > the LVDS receiver has an internal 100 Ohm termination across two LVDS > > inputs, then when the I-V measurements are taken for one input, how is > the > > partner input being treated? Is it left floating? > > > > Thaks, > > Adam > > > > |---------+---------------------------> > > | | Peter LaFlamme | > > | | <plaflamm@amcc.c| > > | | om> | > > | | Sent by: | > > | | owner-ibis-users| > > | | @eda.org | > > | | | > > | | | > > | | 07/23/02 09:01 | > > | | AM | > > | | | > > |---------+---------------------------> > > > > -------------------------------------------------------------------------------------------------------------------------------|
> > > | > | > > | To: ibis-users@eda.org > | > > | cc: > | > > | Subject: [IBIS-Users] LVDS RECEIVER TERMINATION Question > | > > > > -------------------------------------------------------------------------------------------------------------------------------|
> > > > > Hi All, > > I am tasked with creating an IBIS model for an LVDS receiver cell that > has > > an internal 100 ohm termination between the P and N nodes. I had asked > Bob > > Ross about this a while ago and as usual he was very helpful. From his > > response I used the following > > implementation: > > > > |**************************************************************** > > | Component: LVDSRCV > > |**************************************************************** > > | > > [Component] LVDSRCV > > [Manufacturer] AMCC > > | > > | > > | > > [Package] > > | variable typ min max > > R_pkg 1E-3 NA NA > > L_pkg 1E-9 NA NA > > C_pkg 1E-12 NA NA > > | > > [Pin] signal_name model_name R_pin L_pin C_pin > > 1 PAD lvdsrcv NA NA NA > > 2 PADN lvdsrcv NA NA NA > > | > > [Series Pin Mapping] pin_2 model_name function_table_group > > 1 2 rterm_100 > > > > | > > [Diff_pin] inv_pin vdiff tdelay_typ tdelay_min > > tdelay_max > > | > > 1 2 0.2 0 0 0 > > > > [Model] rterm_100 > > C_comp 0.1pF 0.1pF 0.1pF > > > > Model_type Series > > |variable R(typ) R(min) R(max) > > [R Series] 100 80 120 > > > > [Temperature Range] 25.00 125.00 0.00 > > [Voltage Range] 1.800 1.650 1.950 > > > > > ****************************************************************************************
> > > > > I was able to get the model past the IBIS checker but my simulations did > > not show the 100 ohm terminator. I was using a tool which I believe does > > not support this implementation (no need to mention names). I have seen > > other implementations where I believe > > a "Dynamic clamp" is used to model the termination behavior, but I am > > unsure. Can anyone guide me to some reference material or weigh in with > > your experience or help. > > > > Thanks alot, > > Peter > > > > -- > > Peter LaFlamme > > > > Applied Micro Circuits Corp. > > System Applications Engineer > > 200 Minuteman Rd, 3rd Floor > > Andover, MA 01810 > > > > 978-247-8470 phone > > 978-623-0055 Fax > > |------------------------------------------------------------------ > > |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 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
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