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The Photon
The Photon
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Okay, as promised, here's mine:

schematic

simulate this circuit – Schematic created using CircuitLab

As I mentioned in comments, it's excessively complicated, compared to Olin's. The only advantage this has is that the output voltage doesn't go above ground in the high state, which isn't even required for my circuit (but might be useful in another situation).

What makes it work at all, is using a complimentary pair with integrated bias resistors, like MUN5311DW1. This puts R1, R2, R3, R6 and both BJT's into a single SC-70 (2 x 2 mm) package, priced under $0.05 in volume (into the noise for my purposes). Under part number NSBC114EPDP6T5G, the chip can be had in a 1 x 1 mm SOT-963.

I think with the two external discretes, this circuit actually fits a slightly smaller footprint than Olin's, due to the reduced external discretes. Unless I can find a BJT with integrated emitter resistor.

Russell's idea of just using a zener and a resistor probably wins the footprint prize, but unfortunately I don't have the luxury of time to "play a little" to find the correct zener value on this particular project.

Okay, as promised, here's mine:

schematic

simulate this circuit – Schematic created using CircuitLab

As I mentioned in comments, it's excessively complicated, compared to Olin's. The only advantage this has is that the output voltage doesn't go above ground in the high state, which isn't even required for my circuit (but might be useful in another situation).

What makes it work at all, is using a complimentary pair with integrated bias resistors, like MUN5311DW1. This puts R1, R2, R3, R6 and both BJT's into a single SC-70 (2 x 2 mm) package, priced under $0.05 in volume (into the noise for my purposes). Under part number NSBC114EPDP6T5G, the chip can be had in a 1 x 1 mm SOT-963.

I think with the two external discretes, this circuit actually fits a slightly smaller footprint than Olin's. Unless I can find a BJT with integrated emitter resistor.

Russell's idea of just using a zener and a resistor probably wins the footprint prize, but unfortunately I don't have the luxury of time to "play a little" to find the correct zener value on this particular project.

Okay, as promised, here's mine:

schematic

simulate this circuit – Schematic created using CircuitLab

As I mentioned in comments, it's excessively complicated, compared to Olin's. The only advantage this has is that the output voltage doesn't go above ground in the high state, which isn't even required for my circuit (but might be useful in another situation).

What makes it work at all, is using a complimentary pair with integrated bias resistors, like MUN5311DW1. This puts R1, R2, R3, R6 and both BJT's into a single SC-70 (2 x 2 mm) package, priced under $0.05 in volume (into the noise for my purposes). Under part number NSBC114EPDP6T5G, the chip can be had in a 1 x 1 mm SOT-963.

I think this circuit actually fits a slightly smaller footprint than Olin's, due to the reduced external discretes. Unless I can find a BJT with integrated emitter resistor.

Russell's idea of just using a zener and a resistor probably wins the footprint prize, but unfortunately I don't have the luxury of time to "play a little" to find the correct zener value on this particular project.

Source Link
The Photon
The Photon
  • 133.9k
  • 4
  • 173
  • 319

Okay, as promised, here's mine:

schematic

simulate this circuit – Schematic created using CircuitLab

As I mentioned in comments, it's excessively complicated, compared to Olin's. The only advantage this has is that the output voltage doesn't go above ground in the high state, which isn't even required for my circuit (but might be useful in another situation).

What makes it work at all, is using a complimentary pair with integrated bias resistors, like MUN5311DW1. This puts R1, R2, R3, R6 and both BJT's into a single SC-70 (2 x 2 mm) package, priced under $0.05 in volume (into the noise for my purposes). Under part number NSBC114EPDP6T5G, the chip can be had in a 1 x 1 mm SOT-963.

I think with the two external discretes, this circuit actually fits a slightly smaller footprint than Olin's. Unless I can find a BJT with integrated emitter resistor.

Russell's idea of just using a zener and a resistor probably wins the footprint prize, but unfortunately I don't have the luxury of time to "play a little" to find the correct zener value on this particular project.