[AN2834] Is the LM235 a temperature sensor or voltage reference? (Errata?)

[#1]

​Hi,

Maybe the TL431 is a voltage reference.

[Tesla DeLorean]

LM236 ? But I think that's a hack of the LM235 with a leg cropped off...

https://www.ti.com/lit/ds/symlink/lm336-2.5.pdf?ts=1655053986350&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM336-2.5

[#3]

(Does the website only accept 1 attachment in responses?)

I don't believe it was done on purpose, I believe it might be a typo, and the text editor went on to suggest the LM235. The equivalent internal schematic is not the same for LM235 and LM236.

[Tesla DeLorean]

>>I don't believe it was done on purpose..

Have to be super-class dyslexic to get from LM235 to TL431

Much more probable it's being used as a QND two-terminal shunt voltage reference, NatSemi style, and in the context of the quoted usage.

@Peter BENSCH​ do you have an examples of this usage within ST?

You can only have a single file attachment per post, but can add multiple images.

[#5]

Let me understand:

1- LM235 is what is in the referred document AN2834.

2- TL431 I cited as an example of what a voltage reference is.

3- LM236 was quoted later (which seems to be better suited to be in the document rather than LM235)

4- Dyslexia is quite real these days, and is more evident when a person is tired.

5- This question is directed to ST employees who have access to review the document.

6- I don't mean to be rude, but apart from the LM236 quote there seems to be no addition when commenting on other things.

7- Thank you for your attention.

[Peter BENSCH]

@Community member​ Thanks for bringing this to our attention. Indeed, the LM235 is a temperature sensor and the reference in AN2834 is therefore a typo. As a voltage reference for 2.5V, you can use instead e.g. TL1431A (0.25%) or TS824AILT-2.5 (0.5%), which are also available with lower accuracy (without suffix A).

I don't have an application example at the moment, but the use of Vref+ should be quite easy as long as you respect the permissible voltage range for Vref+ and decouple GND and Vref+ cleanly (appropriate layout, LC filter, possibly ferrites).

Regards

/Peter

@Amel NASRI​ Please pass this on to the division so that the typing error can be corrected.

[Amel NASRI]

Hi All,

We confirm that this is a typo where LM236 is meant as already mentioned in page 25 of the same document.

The application note will be updated to replace LM23x by TL1431A as a reference voltage.

Internal ticket number: 130288 (This is an internal tracking number and is not accessible or usable by customers).

-Amel