Subject: [IBIS-Users] ECL Termination Voltage Question
From: Fisher, Thomas (tomfisher@ti.com)
Date: Fri Jan 09 2004 - 11:16:25 PST
All,
I have a PECL driver that I am modeling that has a non-standard load (pi
network to ground) which results in a larger Vod. (1.2-V vs. 800mV) What
happens during simulation is the single-ended waveform depicts a slowness of
the rising edge which results in a plateau effect on the rise/fall of the
differential waveform. (It looks great when simulating in TISpice) Most
(P)ECL termination is going to be 50 ohms to Vtt for both non-inverting and
inverting outputs whereas Vtt = Vcc - 2-V. Under the load I am simulating
we are using 200 ohms to ground. (customers' request)
Having said that, looking in the 3.2 spec on page 78 under ramp rates
model_type for output_ECL it mentions 50 ohm resistor to the termination
voltage (Vterm = Vcc - 2-V). Is this Vterm embedded into the
specification? Is there a way to specify that the load is 200 ohms to
ground? I believe this might be causing the abnormality. Any help/insight
would be appreciated. Thanks in advance.
Regards,
Tom Fisher
|------------------------------------------------------------------
|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
This archive was generated by hypermail 2b28 : Fri Jan 09 2004 - 11:18:28 PST