I am using several NPN/PNP pairs in a circuit. One of the NPN is left unused.

Do I need to do anything, or just leave all 3 leads of NPN floating or I need to connect them for improved stability? If so how?

Thank you.

  • \$\begingroup\$ What's the part number? Some packages have a pin labeled "substrate." If so, then that pin should usually be connected to the most negative point in your circuit (the collectors of both NPN and PNP may be isolated from the substrate by an integral diode.) But see the datasheet for more. So what's the part number? \$\endgroup\$ – jonk Nov 7 '19 at 3:05
  • \$\begingroup\$ Hi jonk, thanks for your reply. The part number is BC846BPDW1T1G. \$\endgroup\$ – Zilaihong Nov 7 '19 at 4:57
  • 2
    \$\begingroup\$ Thanks. I don't see any specification about coupling between them, thermal or otherwise. I don't see a substrate indicated. So I'd take the position, ignorant better information, that they are not on a common die but are instead two dice, separately wire-bonded to the lead frame. (You may want to test this, though.) Can you just call an OnSemi FAE (or whatever they call themselves) and simply ask? (They may have a PDF on the topic at the OnSemi website. But I'm not feeling like doing a search, right now.) \$\endgroup\$ – jonk Nov 7 '19 at 5:10

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