TXB0102 OE

Trey German289

Mastermind 22025 points

Other Parts Discussed in Thread: TXB0102

I'm using a TXB0102 and on my first round of boards I directly tied OE to VCCA. When I wiggle the B pins, the A pins do not wiggle. Could this be because OE is ramping with VCCA?

Thanks,

over 10 years ago

0 Jennifer Joseph over 10 years ago

TI__Intellectual 2530 points

Hi

You can tie OE high to Vcca. This is often done when there is no need to make the pins high impedance.

VCCA must be less than or equal to VCCB and must not exceed 3.6 V

It is better to pull down unused I/O with pull down resistor. The pull-down resistor value should be more 50k ohm.

Thanks

0 Trey German289 over 10 years ago in reply to Jennifer Joseph

TI__Mastermind 22025 points

Hi Jennifer,

I did some more digging and it turns out OE wasn't my problem at all! My input signals on the B side were only toggling between 0-2V. Injecting 5V caused the TXB's output to go high.

The weird thing is when I depopulated the TXB from the board my input signals went back up to 5V. The signals are generated by an optical encoder powered by 5V:

Do you know why the TXB would be clamping the signal to 2V? Could the input/output of the two devices be incompatible?

0 Trey German289 over 10 years ago in reply to Trey German289

TI__Mastermind 22025 points

Turns out the encoder was just poorly documented and required pull up resistors. Thanks for your help.

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TXB0102 OE