Hyperlynx IBIS : What is cmos25_io_r50

Hello Benjamin_Couillard,

I am pretty sure you would have sorted this out by now.

however just for the benefit of future readers / users who might stumble across this thread.

if you do not explicitly set a current strength for your I/O standard, i.e. you do not change the default I/O Standard in Pin Planner, then the current strength will be set to the default settings for the device.

https://www.altera.com/support/support-resources/knowledge-base/solutions/rd08292012_329.html

So for your case, since i assume you left the I/O standard / current strength settings as the default values in Quartus, that is why you see the 50-ohm series termination without calibration in your generated IBIS model =)

You can double check this in your Fitter Report.

just giving you 2 scenarios to help explain the differences a little more clearly.

scenario# 1

setup in pin planner

- I/O Standard = 2.5 V (default)

- Current Strength = 12mA (default)

fitter report

name

pin#

i/o bank

i/o standard

current strength

termination

led0

AK3

3B

2.5 V

Default

Series 50 Ohm without Calibration

scenario# 2

setup in pin planner

- I/O Standard = 2.5 V

- Current Strength = 12mA

fitter report

name

pin#

i/o bank

i/o standard

current strength

termination

led0

AK3

3B

2.5 V

12mA

Off

thanx.

Hi,

You could find the naming nomenclature of the Arria II GX IBIS model in the Notes section of the .ibs file. Specific to the r50 and d4, you can refer to the following text extracted from the .ibs file:

d12 - 12mA Current Strength

r25 - 25 Ohm series on-chip Termination without Calibration

r50c - 50 Ohm series on-chip Termination with Calibration

r50 (without the 'c') mean 50 Ohm series on-chip Termination without Calibration

cmos25_io_r50 is refer to 2.5V LVCMOS I/O model with 50 ohm series on-chip termination without calibration

Here is the example for naming convention on Stratix V IBIS models can be your references:

https://www.altera.com/support/support-resources/knowledge-base/solutions/rd02082012_252.html