74LS11N

[ledwig]

Should the GND and VCC pins of the LS7411D and the LS7411N show connected to net GND and net VCC respectively?

When I go to properties, pins for these two components, those pins are not connected to any nets.

Contrast this to the 7404N, which automatically shows connected to nets VCC and GND.  All 3 are on the attached layout.

[Tien_P]

Hi,

All components in the 74STD_IC, 74S_IC and 74LS_IC family show the VCC and GND pins and you have to wire these pins yourself.  Some people prefer to show power and ground connection on the schematic.  If you use digital components that have hidden power and ground pins, these parts doesn't require you to make the connection.

[ledwig]

How can I wire the VCC and GND pins of an LS7411N to the VCC and GND nets used by digital components that have hidden power and ground pins?

[Tien_P]

Hi,

Have a look at this Knowledge Base.

[ledwig]

That KB does not show how to manually make a connection to the global power and ground nets.

The KB only shows how to verify whether the virtual connection is made.  That is how I found out the VCC and GND nets are not automatically connected for the LS7411N.

If you have both an LS7411N and a 7404N in the same circuit, can you conect the VCCs together?

[Tien_P · Accepted solution]

Hi,

You have to place a VCC and GND symbol on the work area and it will automatically connect to the IC.  In this example, both U1 and U2 are connected to the digital ground and VCC.

[ledwig]

I took your digital example and added a 74LS11N.

Look at the pins of the 74LS11N.  The VCC and GND did not automatically connect, even with the VCC and GND symbols that you placed on the work area.

[ledwig]

My appologies.  I failed to add the wires from my 74LS11N to the VCC and GND.

You have solved my problem.

Thank you.