PZT2222 says both pins 2,4 are connected, do you have to connect both?

[alank2]

The datasheet for PZT2222 says both pins 2,4 are connected.  When routing tracks, do you have to connect both?

[ConKbot]

For an sot-223, or other 3 pin + thermal tab transistors, no you don't have to connect both, as the middle pin and tab are connected in the leadframe. But verify that there isnt exposed metal between the center pin and thermal tab. SOT-89 can have this, so running a trace, there would only be soldermask providing insulation.

[flynwill]

No you don't need an additional connection.  They are literally the same chunk of metal inside the plastic.  The "tab" is there for heat-sinking, so depending on how much power the part will be dissipating in your design the PCB may need a significant copper area connected to the tab, an added heat sink or both.

[alank2]

Thanks guys.  I'm using a part that has no connection between the pins on the underside, I did look at one like that, but it seemed like you could get a bridge between that and pins 1 and 3 pretty easily so I moved to the SOT223 instead.  I'll route the track if it is easy to, but if I need to route another track through it I'll just connect one or the other.  I'll make sure there is enough copper on the larger tab for heat sinking.