ChrisP58 Well-Known Member Most Helpful Member Mar 28, 2023 #1 So, the Base-Emitter junction of a BJT is essentially a diode. My interest is purely economic. I have a circuit that uses a PNP (2N3906) that is also connected to a diode (1N4148). I can get a dual PNP in a SOT-363 package. By using half of it for the diode, there is only one part to buy and populate. It simulates just fine in Ltspice. But are there any non obvious potential issues with using it as such?
So, the Base-Emitter junction of a BJT is essentially a diode. My interest is purely economic. I have a circuit that uses a PNP (2N3906) that is also connected to a diode (1N4148). I can get a dual PNP in a SOT-363 package. By using half of it for the diode, there is only one part to buy and populate. It simulates just fine in Ltspice. But are there any non obvious potential issues with using it as such?
danadak Well-Known Member Most Helpful Member May 23, 2023 #21 I was just looking at that -slope portion of Vbe curve as current is increasing, a potential oscillator in the making..... Upvote 0 Downvote
I was just looking at that -slope portion of Vbe curve as current is increasing, a potential oscillator in the making.....
Lightium Active Member May 23, 2023 #22 I hope this don't become trend and markets adjust forcing the rest-of-us to do the same. Upvote 0 Downvote
crutschow Well-Known Member Most Helpful Member May 23, 2023 #23 ChrisP58 said: I can get a dual PNP in a SOT-363 package. Click to expand... Are the two transistor totally isolated from each other? Upvote 0 Downvote
ChrisP58 said: I can get a dual PNP in a SOT-363 package. Click to expand... Are the two transistor totally isolated from each other?
ChrisP58 Well-Known Member Most Helpful Member May 23, 2023 #24 crutschow said: Are the two transistor totally isolated from each other? Click to expand... Yes. At least that is my interpretation of the phrase "two discrete devices" in the datasheet. It has been interesting to follow this thread. I've changed my circuit to use both parts as transistors, so will use a diode for the diode. Upvote 0 Downvote
crutschow said: Are the two transistor totally isolated from each other? Click to expand... Yes. At least that is my interpretation of the phrase "two discrete devices" in the datasheet. It has been interesting to follow this thread. I've changed my circuit to use both parts as transistors, so will use a diode for the diode.
Beau Schwabe Active Member May 24, 2023 #25 To the OP - Depending on the original circuit, it "might" make a difference when using a diode vs. a transistor. For example in a current mirror circuit ... See Simulation: https://kit-start.com/Forum/Schematic%20Simulation%2005_24_2023.html Upvote 0 Downvote
To the OP - Depending on the original circuit, it "might" make a difference when using a diode vs. a transistor. For example in a current mirror circuit ... See Simulation: https://kit-start.com/Forum/Schematic%20Simulation%2005_24_2023.html