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I have downloaded the lm7905 from this source: https://github.com/kafana/ltspice-misc/blob/master/models/regulators.lib

unfortunately, it seems that the output voltage is 0mV all the time (the green value on the included picture). I am trying to get -5V as the output. Did any one else have a similar problem? Do you maybe know, how to get it working right? The lm7805 for 5V seems to work fine.

enter image description here

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    \$\begingroup\$ Where is n007 and n006? \$\endgroup\$
    – Transistor
    Apr 12, 2021 at 18:01
  • \$\begingroup\$ @Transistor That's my problem, too: I only see two nodes, so they should be N001 and N002. Does the Mac version not do the auto-renaming (if not manually done)? \$\endgroup\$ Apr 12, 2021 at 18:25

2 Answers 2

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This might not be a 100% correct component model. However, you're not loading the output, and without any resistive load, the LM7{8/9}xx series isn't known for accuracy.

So, add a 1 kΩ resistor from OUT to GND, and observe again.

If it still doesn't do anything, either the SPICE model is wrong, or you're not actually observing the right node.

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Works okay for me except output is not very accurate (-5.32V, which is out of spec).

Maybe your symbol pins do not match the model or you are on the wrong node- it is better to name the nets you are plotting (F4 and, say, Vout) so there is no question of what node it is.

Also note that if you edit the schematic the node numbers may change but the plot will continue plotting the same node number, which may be confusing. Naming the node prevents that oopsie.

(P.S. I added a small ~10mA load to put it within the guaranteed range of 5mA < Iout <1A and added an ESR of 1 ohm to the output capacitor to emulate a tantalum cap when I did the test, just to be sure- it made no significant difference).

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    \$\begingroup\$ Same here: it works, with or without load, but not very precise (down to 10 Ohms and same output). \$\endgroup\$ Apr 12, 2021 at 18:26

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