TXB0104-Q1: When unused pin is open

Lee, Sam

Part Number: TXB0104-Q1

Hi team,

What happens if unused pin is open for both side? A customer didn't tie it to GND by mistake. I refer to some comments like below in E2E, but can you explain more easily?

"Unused IO pins for the logic devices are advised to be connected to gnd, however, the TXB is like a weak latch which tries to maintain a defined high or low state."

In addition, is it possible to connect directly the unused port to GND without pull down (100kohm)? Otherwise, does it have to use pull down resistor?

Thanks,

Sam Lee

over 5 years ago

0 Clemens Ladisch over 5 years ago

Guru 317480 points

When both A and B pins are open, they will settle on an unknown but valid voltage level (either low or high).

When you connect them to GND directly, they will be at a low level. The worst that can happen is that during power-up, the edge accelerator might falsely detect a rising edge and try to force the line high for 10 ns.

0 Lee, Sam over 5 years ago in reply to Clemens Ladisch

TI__Expert 6105 points

Hi Clemens,

Thank you for your answer.

Best Regards,

Sam Lee

Logic

Logic forum

TXB0104-Q1: When unused pin is open