Re: PSpice Logic Levels

Sep 05, 2008 1 Replies


Jim Thomps>> >>


>>> Jim Thomps>>>> Along the lines of the question regarding LTspice logic levels...
>>>>
>>>> PSpice has a number of nice digital stimulus "parts", but they kick
>>>> out _very_fast_ edges at 0-5V logic levels when connected to analog
>>>> parts.
>>>>
>>> Can't you set trise and tfall as one can in LTSpice? I just didn't know
>>> where but one kind reader and Helmut explained it.
>>
>> I think they were talking of _sources_. I'm talking of interfaces
>> between digital and analog, so that the extensive _stimulus_ tools can
>> be used at the device level.
>>
>>>
>>>> So, in this past week, I have created some stimulus-level-to-analog
>>>> parts with adjustable levels and rise and fall.
>>>>
>>>> Likewise analog back to 5V logic.
>>>>
>>>> That way I can patch in 74HC stuff just for behavioral analysis...
>>>> speeds things up before I go full device-level in the chip design.
>>>>
>>> I wish the behaviorals could have Rdson in there. But I guess one can't
>>> have everything in life. Well, at least my flu is gone except for a
>>> hacking cough so I'm happy.
>>>
>>>
>>>> Any PSpice users that are interested, I'll send you copies for your
>>>> symbol libraries... PSpice Schematics only... Capture sucks the big
>>>> lemon ;-)
>>>>
>>> So what's your favorite schematic entry tool du jour? Meantime I kicked
>>> the tires on some of them. Big ones like Bartels BAE, small ones like
>>> TinyCad etc., but wasn't too enthused. Then again the BAE is probably
>>> more geared towards chip designers and high-density digital.
>>>
>>> If Eagle offered a hierarchical sheet structure I'd say. But it doesn't :-(
>>
>> Ancient, but VERY user-friendly, PSpice Schematics does hierarchical
>> designs far better than OrCAD Capture.
>>
>
>OrCad SDT was very good. I am more and more tempted to go back to that.
>None of the "new and improved" high-faluting Windows CAD packages has
>ever reached its robustness.
>
>But I want to change only one more time because every time you switch
>it's new libraries, new schematic file formats, new everything.

OrCAD SDT can _easily_ be converted to PSpice Schematics; and PSpice Schematics can be relatively easily converted to Capture... as long as you are aware of the potential netlisting anomalies.


...Jim Thompson

| James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | It\'s what you learn, after you know it all, that counts.

Yes, I remember going from SDT to PSpice with ease although back then I entered Spice via a text editor. Main reason was that my first laptop used less power when not in graphics mode so the battery would last. In the 80's/90's laptops had a really useful battery lifetime.

I wonder how many people and maybe companies stuck to this old DSO-OrCad. The Yahoo group appeared to be very paltry last time I checked.

Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.

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