I found a very nice voltage regulator of ST (LD39300). But the LD39300PT-R has a package with a lifted central pin (TO-252-5, DPak (4 Leads + Tab), TO-252AD). Here is a photo:


I just want to do a routing of my PCB but I don't know how to solder the central ground pin.

With an extra cable?

Why is the central pin not manifactured like the rest?


It's interesting that the datasheet doesn't seem to mention this, but it's pretty clear that the mounting tab is supposed to be used for the ground connection, not the truncated middle pin.


While not explicitly stated in the datasheet, Ground Pins, even floating stubs like pin 3 in the PPAK or pin 2 in the DPAK, are normally tied to the heatsink tab on the package. You need to mount the dpak on a heatsink, or to the copper on the pcb, and that should be connected with the ground plane for your PCB.

You can test this by using a multimeter in continuity mode, between the tab and the pin 3.

  • \$\begingroup\$ This package is designed so the tab is always soldered to copper on the PCB. \$\endgroup\$ – user3624 May 29 '13 at 21:00

protected by clabacchio May 29 '13 at 20:14

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