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Tool/software:
Hi team,
Could you let me know SN74LVTH244A initial output state when input is floating?
I understand the device has bus hold feature. But my customer would like to know the state when powering up while the input is floating.
As the device is TTL, my customer expects low output.
Best regards,
Kazuki Itoh
Hi Clemens-san,
Thanks for your comment.
Any comment from TI apps team?
Best regards,
Kazuki Itoh
Hi Itoh-san,
Clemens is correct. There is not way to know exactly which state it is during powerup. See datasheet section below:
Hi Albert-san,
Thanks. Could you let me know the output state after powering up while the input is floating as well?
The /OE is fixed to low, so my customer assumes the input affects the output.
Best regards,
Kazuki Itoh
The bus-hold circuit ensures that an open input stays in the previous state. So the state that happened during power-up will not change.
Hi Clemens-san, Albert-san,
Thank you for clarification.
Let me add some background.
My customer is using SN74LVTH244A for board-to-board communication.
The customer's system update requires to remove the prior stage board, which requires to determine the initial state of 244 while the input is NC.
As my customer wants the initial output state fixed to low, my customer understands that the input needs to be tied to GND.
Best regards,
Kazuki Itoh
Yes, the inputs need to be tied to GND. (When using pull-down resistors, they must be stronger than the bus-hold.)