SN74LV123A: How to handle unused pins

This is strange. I do not understand where a high current could flow. And letting the C_ext/R_ext pin float does not sound like a good idea.

Anyway, just use the SN74LVC1G123.

Hi Clemens,

Thank you for suggesting another device. But since my customer plans to use SN74LV123A, we want to know what to do with this device. 

Is there any other idea to solve this problem? Or, is there some information which I should ask customer?

By the way, the competition device (HD74LV123A) has the following description:

"The input pins for unused circuit should be used under conditions to fix the outputs to avoid malfunction cased by noises. Also, it's recommended that Rext / Cext terminals are open and external parts are not connected to."

https://www.renesas.com/jp/ja/document/dst/hd74lv123a-rej03d0314-0600z?language=en&r=527206　

Hi Malcolm,

Thanks for the information. If possible, would you like to know why it's fine to leave these pins floating, do you have any information? 

Best regards,

Hiromu

Hi Malcom,

Do you have any idea on why a abnormal heat issue happened by connecting the Rext and Cext pins to GND?

Regards
Ohashi

Hi Malcolm,

My customer wants to double check the internal circuit.

In this app note, seems that there is only low side FET for Rext and Cext.

https://www.ti.com/jp/lit/an/slva720a/slva720a.pdf

But in the below FQA, seems that there is high side p-FET between Vcc and Rexc/Cext. Seems that this FET was causing the heat issue in some kind of situation.

https://e2e.ti.com/support/logic-group/logic/f/logic-forum/863529/faq-how-does-a-monostable-multivibrator-one-shot-work

Which configuration is correct?

Regards
Ohashi