Jerry,


You can hide the pullup in the PowerClamp, such as:


<smaller><smaller>[POWER Clamp Reference]                2.5V       NA   
    NA

[POWER Clamp]

-2.5V  16.67mA  NA  NA | Use: V= -1*[POWER Clamp Reference], I=([POWER
Clamp Reference]/resistor_value)

 0.0V      0mA  NA  NA 

 2.5V -16.67mA  NA  NA | Use: V=[POWER Clamp Reference], I= -1*([POWER
Clamp Reference]/resistor_value)

</smaller></smaller>

This example ties a 150 Ohm resistor to 2.5 volts and leaves it there
even if the output tri-states.


Donald Telian

CADENCE



At 05:51 PM 10/01/1999 -0400, Jerry Hayes wrote:

>

>I am attempting to create a v2.1 ibis model for a driver that is

>essentially an I/O_open_drain with internal pullup termination.

>I have created various ibis models for this driver ... however none

>of them are correlating well to spice due to the internal pullup.

>Can anyone suggest the proper modeling technique for this type of

>driver?  Helpful suggestions are greatly appreciated.

>

>Thanks,

>Jerry Hayes

> 

>

>

>

Donald Telian

Cadence Design Systems

phone: 408-944-7791

email: donaldt@cadence.com