LTspice has the following symbol for XOR gate:

enter image description here

But as far as I can see the XOR gate has two inputs.

  • 1
    \$\begingroup\$ Never look a gift horse in the mouth. \$\endgroup\$
    – Andy aka
    Jun 12, 2019 at 11:43
  • \$\begingroup\$ @Andyaka Their weird XOR has three terminals at the output. Very weird or do I.. \$\endgroup\$
    – cm64
    Jun 12, 2019 at 11:46
  • \$\begingroup\$ The output with a circle is an inverting output, creating an XNOR gate. \$\endgroup\$
    – Simon B
    Jun 12, 2019 at 13:00

1 Answer 1


From LT wiki:

The reason that these gates are implemented like that is that this allows one device to act as 2-, 3-, 4- or 5- input gates with true, inverted, or complementary output with no simulation speed penalty for unused terminals.


The exclusive XOR device has non-standard behavior when more than two inputs are used: The output is true only when exactly one of all inputs is true. Use the associative property of XOR's with multiple XOR devices to implement an XOR block with more than two inputs.

  • \$\begingroup\$ The thing is I was expecting two inputs and a single output. Now there are 5 inputs and 3 outputs. I just need to use this as a usual XOR but I dont know how to use the inputs and outputs with their XOR. Do you have any hint? It is not clear which terminal is output for instance there are three pins. \$\endgroup\$
    – cm64
    Jun 12, 2019 at 11:45
  • 3
    \$\begingroup\$ Read the rest of the wiki entry. It's all there. If you just want a 2-input XOR, use the top two inputs and the top output. Connect the rest of the inputs to pin 8 (which should be grounded), and ignore the other output. \$\endgroup\$
    – Dave Tweed
    Jun 12, 2019 at 11:47
  • \$\begingroup\$ Just being a bit pedantic: you can use up to 5 inputs in any order, and unused inputs can be left floating, or connected to whatever other different net the 8th pin (ground pin) is connected (the floating inputs will automatically have the same connection). Also, it only has two outputs, complementary logic, not three. \$\endgroup\$ Jun 12, 2019 at 18:29

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