Does LM239 Support Hysteresis?

[john239955_stm1_stmicro_com]

Can this, or another, hysteresis circuit work with LM239?

LM239 datasheet doesn't mention hysteresis.

https://www.digikey.com/product-detail/en/stmicroelectronics/LM239DT/497-2973-1-ND/634871

[#2 · Accepted solution]

Google is our friend.

https://www.google.com/search?q=LM339+vs+lm393

https://datasheet.lcsc.com/szlcsc/3PEAK-LM393-SR_C93150.pdf

[john239955_stm1_stmicro_com]

Thx, should have occurred to me to look at a different manufacturer's datasheet. I wonder why STM's datasheet doesn't include that.

This search gives additional detail:

https://www.google.com/search?q=%22lm239%22+external+%22hysteresis%22

http://www.ti.com/lit/an/snoa654a/snoa654a.pdf

see section 4 Comparators with Hysteresis

[john239955_stm1_stmicro_com]

3peak:

TI: 

I'm wondering if the circuit would be different for a single supply. In my application, i'm making an over 0V detector, with a switchpoint of about 50 mV on the upward swing. Therefor, my ref would be connected to Ground.

Your 3peak sheet shows no ref R, but the other sources do show a ref R. What's the function of the ref R? What's drawback of not using it? Is it needed with the LM239 and a single-supply?

Same question re input R. The TI sheet one, but the other sources don't.

Same question re pullup R on the output.

thx

[#5]

To understand this type of circuit, it is necessary to study operational amplifiers and comparators.

Sorry, but I believe this is not the best place to get help with general electronics issues. Perhaps a forum with a larger community can help you with questions not directly related to the component itself.

Maybe in the general electronics section of the Arduino forum you can receive answers to questions of this nature, but it would be great if you could take an analog electronics course, there are free online courses on the internet, if you can research about it.

https://forum.arduino.cc/index.php?board=5.0

https://www.eevblog.com/forum/chat/?PHPSESSID=hn25i7vcgq9vinb4hp18cc2de0

[john239955_stm1_stmicro_com]

Ok, understood. Thx!