I have a L79L05 from ST Microelectronics, which has the following pinout: L79L05 pinout

I have created a symbol and package in Eagle for that component. The symbol has three pins - IN, OUT and GND, while the package has 8 pads. When creating device, I connected pads 2, 3, 6 and 7 to the IN pin. As a result, in board editing mode, Eagle adds airwires that asks me to connect all these pins on PCB:

Unwanted airwires

Of course I can overcome these airwires by either ignoring it, or by creating a symbol which has 8 (or 6, as two marked as NC) pins, and assign some of them to a same swap network. But I would like to find a better solution, if there is one.


1 Answer 1


You should solder all the pins and use both in and both out pins for the connection to your traces on the PCB. Combining multiple adjacent pins, especially on thin-pitch ICs, is done to allow for better thermal and inductive behaviour of the respective connection.

A Quote from the L79L datasheet:

Our SO-8 package used for Voltage Regulators is modified inter nally to have pins 2, 3, 6 and 7 electrically communed to the die attach flag. This particular frame decreases the total thermal resistance of the package and increases its ability to dissipate power when an appropriate area of copper on the printed circuit board is available for heat-sinking. The external dimensions are the same as for the standard SO-8.

  • \$\begingroup\$ Actually I didn't thought about heat dissipation issues. Makes sense, thank you. \$\endgroup\$ Commented Sep 1, 2014 at 18:47

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