LM311: a hysteresis in LM311

Hello Vladimir,

The LM311 is unique in that you can have two output options:

Open Collector, with the emitter grounded, and a pull-up resistor between the collector to the logic high voltage. This is the most common configuration. Feedback should go back to the positive node.

Open Emitter, with the collector to the logic high voltage, and a pull down resistor from the emitter to GND. When in open emitter configuration, THE OUTPUT LOGIC IS INVERTED. Feedback should go back to the NEGATIVE node.

Which output configuration are you planning to use?

oops..slight error...post corrected - please read online.

Dear Paul, thank you. I use Open Collector, with the emitter grounded, and a pull-up resistor between the collector to the logic high voltage. Feedback resistor should be between collector and "+IN" ?

Hello Vladimir,

Yes.

For more information, please see the appnotes below. Though it uses different devices, the principle is the same.

Comparator with and without hysteresis circuit (Rev. A)

Non-inverting comparator with hysteresis circuit (Rev. A)

Inverting comparator with hysteresis circuit (Rev. A)

Hi Vladimir,

I would run a TINA-TI simulation:

vlad_lm311.TSC

Kai

Thanks Kai

Vladimir

If further support is required, feel free to let us know.  Otherwise, we are considering this closed.

Thanks for your support of the forum.

Chuck

Dear Kai, thank you!