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February 7, 2018 11:12

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How to design a 7400 having 4 single gates to place?

How can I design a 7400 (it has 4x NAND gates) so that I can place single NAND gates in the schematic editor?

What I've tried:

Using the parts/library editor I  made a new component holding that 4 NAND. As the second step I wanted to assign the ICs pins (14). Assigning the pins to the 4 NANDs wasnt a problem but it wasnt possible to assign pin7 to GND and pin14 as Vcc because these pins havent been in the assignment list/editor. What did I wrong?

Thanks for your help



0 Votes

February 12, 2018 08:48

Hi Peter, not quite sure what went wrong, but you can define the 7400 as 4 or 5 gates.
If the 4 gates option which looks neater in my view you define a schematic symbol for 2i/ps and 1 o/p and use this 3 times. The fourth gate has the two power pins as well.

If you enable the installed legacy libraries (mainly through hole parts) there is a 74LS family which illustrates multi gates, but they were created using pwr to each gate i.e. 5 pins per NAND function which is a bit messy in my view.