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| Searching for an optocoupler with MOSFET output stage |
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| Lupin III.:
I'm looking for an optocoupler that has a MOSFET output stage and not the usual bipolar output transistor. I have an analog pin on a chip that I want to pull really close to ground (via an isolated signal), which means that the saturation voltage of a bipolar transistor is already too high. The current will be very low (<1mA), so the internal resistance doesn't matter. Switching speed isn't an issue either. As long as an about 1kHz square wave can get through it's fine. I can't really find such a component that's also easily available and rather cheap (~1€/piece would be nice since I need multiple of them). Has anyone got any suggestions? |
| Wimberleytech:
The physics of a bipolar junction transistor make it very amenable to use as an opto-coupler...MOSFET device physics does not. Could an opto be fabricated in a process that has both MOS and bipolar (e.g., BiCMOS)? Yes, of course, but it would be more expensive and why? I rather doubt one exists. |
| up8051:
MOUSER: All Products => Optoelectronics => Optocouplers / Photocouplers => MOSFET Output Optocouplers |
| Wimberleytech:
--- Quote from: up8051 on January 06, 2020, 05:00:16 pm ---MOUSER: All Products => Optoelectronics => Optocouplers / Photocouplers => MOSFET Output Optocouplers --- End quote --- Well, shut my mouth. I have been schooled...lol! Looking at the datasheet, it appears that they just put an output stage on a more-or-less conventional opto circuit. |
| oPossum:
There are even depletion mode MOSFET optos that are normally closed. |
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