Thank you for the reply Arpad.
I will add the termination model to the IBIS model to see if it works.
Regards,
Shiva
On Mon, Jan 9, 2017 at 10:25 PM, Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx>
wrote:
Shiva,
Those two B-elements are two single ended Rx models, and as
such they do not include the pin-to-pin 100 Ohm resistor.
IBIS calls this “pseudo differential” models. One way to
solve this is by putting a 100 Ohm resistor between the two
signal nodes.
IBIS also has a concept of “true differential” models, but
I am not sure whether the B-element supports that (I am a
competitor for Synopsys, so I can’t tell). You need to look
at the spec or the IBIS Cookbook, and read up on these two
differential model types.
I hope this helps. Let me know if you have more questions…
Thanks,
Arpad
=============================================================
*From:* ibis-users-bounce@xxxxxxxxxxxxx [mailto:ibis-users-bounce@
freelists.org] *On Behalf Of *Mike LaBonte
*Sent:* Sunday, January 08, 2017 7:25 PM
*To:* shiva20587@xxxxxxxxx; ibis-users@xxxxxxxxxxxxx
*Subject:* [ibis-users] Re: simulating LVDS receiver IBIS model
Shiva,
Maybe the issue here is that IBIS buffers are single ended. There is no
explicit model of differential characteristics. However, a differential
buffer can be extracted as an IBIS buffer model giving a reasonable
approximation in pseudo-differential mode. Was the buffer model extracted
using the methods described in section 4.0 of the IBIS Cookbook (
http://ibis.org/cookbook/cookbook-v4.pdf) ?
Mike
*From:* ibis-users-bounce@xxxxxxxxxxxxx [mailto:ibis-users-bounce@
freelists.org <ibis-users-bounce@xxxxxxxxxxxxx>] *On Behalf Of *Shiva
Kumar
*Sent:* Sunday, January 08, 2017 1:47 AM
*To:* ibis-users@xxxxxxxxxxxxx
*Subject:* [ibis-users] simulating LVDS receiver IBIS model
Hello,
I am trying to run simulations on an LVDS receiver IBIS model with an
internal termination of 100 ohms between P and N pads.
I am basically trying to run DC analysis using HSPICE simulator, I have
about 1.2V at P pad and 1.1V at N pad. With 100 ohms resistor,I would
expect about 1mA flowing through the pads.
But that is not what I am seeing ,the model doesn't act like there is a
100 ohm resistor between pads.
This is how I am instantiating the IBIS files in SPICE and I am
connecting DC voltages to nd_in_p and nd_in_n pads
b_ibs_p nd_pc_p nd_gc_p nd_in_p nd_outof_in_p
+ file = lvdsrcv.ibs
+ model = lvdsrcv
+ typ=typ
b_ibs_n nd_pc_n nd_gc_n nd_in_n nd_outof_in_n
+ file = lvdsrcv.ibs
+ model = lvdsrcv
+ typ=typ
The IBIS model has been created using SPICE simulations sweeping the
voltage source at PAD P and connecting a VCVS source at PAD N ,the 100 ohm
termination is internally connected in the netlist.
Am I missing something here? Is there a problem with the IBIS model below
or with it's instantiation ? Why I am not able to see the affect of 100 ohm
resistor while simulating the IBIS model? Do I need to somehow specify in
the IBIS model about the 100ohm termination ?
Any suggestions would be appreciated.
Regards,
Shiva kumar
[Pin] signal_name model_name R_pin L_pin C_pin
1P P_out lvdsrcv
1N N_out lvdsrcv
VSSI GND GND
VDDI VDDI POWER
[Diff Pin] inv_pin vdiff tdelay_typ tdelay_min tdelay_max
|
1P 1N 100mV 0 0 0
|
|***********************************************************
******************
| Model lvdsrcv
|***********************************************************
******************
|
[Model] lvdsrcv
Model_type Input
Polarity Non-Inverting
Enable Active-High
Vinl = 0.8V
Vinh = 2.0V
C_comp 2.0pF 2.0pF 2.0pF
|
|
[Temperature Range] 25C 125C -40C
[Voltage Range] 2.5V 2.375V 2.625V
[GND_clamp]
|Voltage I(typ) I(min) I(max)
|
-3.3 -0.7089 -0.8256 -0.7802
-3.15 -0.669 -0.7783 -0.7353
-3 -0.629 -0.7309 -0.6902
-2.85 -0.5888 -0.6832 -0.645
-2.7 -0.5484 -0.6355 -0.5996
-2.55 -0.508 -0.5876 -0.5541
-2.4 -0.4674 -0.5395 -0.5085
-2.25 -0.4267 -0.4914 -0.4629
-2.1 -0.3858 -0.4432 -0.4171
-1.95 -0.3449 -0.3948 -0.3713
-1.8 -0.304 -0.3464 -0.3253
-1.65 -0.263 -0.2979 -0.2794
-1.5 -0.2219 -0.2495 -0.2335
-1.35 -0.181 -0.202 -0.1878
-1.2 -0.1403 -0.1561 -0.143
-1.05 -0.1005 -0.1134 -0.1008
-0.9 -0.068195 -0.077483 -0.076116
-0.75 -0.052236 -0.052513 -0.063773
-0.6 -0.04377 -0.037842 -0.053529
-0.45 -0.038265 -0.031578 -0.0466
-0.3 -0.035287 -0.028775 -0.043128
-0.15 -0.032594 -0.026478 -0.03996
-0 -0.029897 -0.024192 -0.036786
0.15 -0.027195 -0.021901 -0.033606
0.3 -0.024488 -0.019606 -0.030422
0.45 -0.021777 -0.017307 -0.027232
0.6 -0.019061 -0.015005 -0.024036
0.75 -0.016341 -0.012698 -0.020835
0.9 -0.013616 -0.010386 -0.01763
1.05 -0.010887 -0.0080711 -0.01442
1.2 -0.0081543 -0.0057526 -0.011206
1.35 -0.0054195 -0.0034316 -0.0079903
1.5 -0.0026827 -0.001109 -0.0047721
1.65 0 0 -0.0015524
1.8 0 0 0
|
[POWER_clamp]
|Voltage I(typ) I(min) I(max)
|
-3.3 0.8268 0.8547 0.8944
-3.15 0.7793 0.8054 0.842
-3 0.7316 0.756 0.7895
-2.85 0.6837 0.7064 0.7368
-2.7 0.6357 0.6567 0.684
-2.55 0.5876 0.6068 0.631
-2.4 0.5393 0.5567 0.5778
-2.25 0.4909 0.5066 0.5245
-2.1 0.4425 0.4565 0.4711
-1.95 0.3939 0.4065 0.4175
-1.8 0.3453 0.3568 0.3638
-1.65 0.2965 0.3074 0.3101
-1.5 0.2479 0.2585 0.2565
-1.35 0.1994 0.2104 0.2034
-1.2 0.1514 0.1639 0.1515
-1.05 0.1056 0.1201 0.1062
-0.9 0.070648 0.081484 0.08064
-0.75 0.054754 0.05341 0.067169
-0.6 0.045541 0.03873 0.055795
-0.45 0.038954 0.032181 0.04747
-0.3 0.035415 0.028921 0.043256
-0.15 0.032705 0.026585 0.040076
0 0.030008 0.024298 0.036902
0.15 0.027306 0.022007 0.033722
0.3 0.024598 0.019712 0.030537
0.45 0.021887 0.017413 0.027347
0.6 0.019172 0.01511 0.024152
0.75 0.016451 0.012803 0.020951
0.9 0.013726 0.010492 0.017745
1.05 0.010997 0.0081766 0.014535
1.2 0.0082649 0.0058581 0.011322
1.35 0.0055301 0.0035372 0.0081059
1.5 0.0027933 0.0012145 0.0048877
1.65 5.5285e-05 0 0.001668
1.8 0 0 0
|
|End [Model] lvdsrcv
