LTSpice and Logic

Mooly · 4th August 2012, 10:59 AM

I wanted to use LTspice for a little circuit using logic but have run into a problem.

The output from the logic gates seems always to be either 1.00 volts or zero. In the "real world" the output would be determined by the supply voltage.

Here's simple circuit to show what I mean. How do I get the output to be a 5 volt or 10 volt (or whatever I want) level.

repycte · 4th August 2012, 11:21 AM

You have to add "Vhigh=5" (for 5V) in SpiceLine of the component.

Mooly · 4th August 2012, 11:50 AM

Thanks for that... I'll have play. Never tried using logic before in LTspice.

Mooly · 4th August 2012, 12:24 PM

Brilliant repycte, that works great... thanks.

marce · 6th August 2012, 12:22 PM

Get better results with a proper digital signal integrity software, but it dosn't come cheap.

4th August 2012, 11:50 AM	#3
Mooly diyAudio Moderator Join Date: Sep 2007	Thanks for that... I'll have play. Never tried using logic before in LTspice. __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

4th August 2012, 12:24 PM	#4
Mooly diyAudio Moderator Join Date: Sep 2007	Brilliant repycte, that works great... thanks. __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

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4th August 2012, 11:21 AM	#2
repycte diyAudio Member Join Date: Feb 2011	You have to add "Vhigh=5" (for 5V) in SpiceLine of the component.

6th August 2012, 12:22 PM	#5
marce diyAudio Member Join Date: Jun 2007 Location: Blackburn, Lancs	Get better results with a proper digital signal integrity software, but it dosn't come cheap.