Hello,
Regarding to pull-up resistor on TM431, my customer is asking some question.
They designed on their board same as TMP431 Basic Connections in datasheet(Figure 20: page 32 )
and they are checking on it now.
The 10k ohm is connect to ALERT pin as pull-up resistor.(Vcc :5V)
They confirmed that the voltage of ALERT pin is 4V at High level output, however THERM pin is 5V at High level output.
When SCL,SDA and THERM pin are opened, but the voltage of ALERT pin isn’t changed. (Keep 4V.)
They confirmed to same phenomenon on other their board.
(Question)
(1) Could you please tell me about the possible cause of 4V at High level output?
(2) They guess that some current is input to ALERT pin from Vcc(5V).
If so, do they need to change value of pull-up resistor? (More than 10k ohm?)
Regards,
Tao2199
