Post Go back to editing

(ADuM14x)What will happen if input is HiZ.

Hi !

I have some questions about ADuM14x.

At our customers system sometime the device which is connected to ADuM14x input outputs HiZ.

So my question are these.

********************************************************************************************************************

Q1)

I already know that ADuM14x don't have internal resistor.

(ADuM14x)Does ADuM14x has internal Pull-up or Pull-down resistor? 

What will happen if all supply are powered and input is HiZ.

I think output will be Indeterminate.

Is this correct?

Q2)

If our customer input HiZ to ADuM14x , would it cause some problem to the device?

For example, some kind of digital device will broke up when input is HiZ.

Q3)

At datasheet , this is written.

What do you mean

"The ADuM140D/ADuM140E/ADuM141D/ADuM141E/
ADuM142D/ADuM142E digital isolators require no external
interface circuitry for the logic interfaces."?

If there is HiZ input mode at system and if the customer want to control the output , I think they should insert Pull-up or down resistor to input pin.

Can our customer do this?

But at the datasheet "digital isolators require no external interface circuitry for the logic interfaces" so I want to ask can our customer insert resistor to the input signal line.

********************************************************************************************************************

Also the competitor chip has internal resistor so it won't be a problem if input is HiZ.

So if our customer have Pull-down/up resistor , it would become disadvantage.

Best regards.

Kawa

Parents
  • Hi Kawa,

    I understand your concern about the HiZ input to our digital isolators, if there is a specific time that the through-current occurs, the high on resistance of MOSFET inside will limit the current and I think the input state has the trend to go to high or low rather than intermediate state. You could add pull-up or pull-down resistors to avoid encountering this specific condition.

    Regards,

    Neil

Reply
  • Hi Kawa,

    I understand your concern about the HiZ input to our digital isolators, if there is a specific time that the through-current occurs, the high on resistance of MOSFET inside will limit the current and I think the input state has the trend to go to high or low rather than intermediate state. You could add pull-up or pull-down resistors to avoid encountering this specific condition.

    Regards,

    Neil

Children
No Data