TXB0102: TXB0102: is OE needed to connected to ground during powering up

Yarn Guo

Part Number: TXB0102

Hi, Team:

My customer wants to use TXB0102 to do 3.3V to 5V level shifting. By reading the datasheet, it looks strongly recommend us to make sure OE pin grounded during powering up. Customer won't like to use a extra GPIO to control the OE pin. What kind of leakage or risk will be present at the output if we only connect OE to Vcca during the system powering up?

Is it safe for us just connect OE pin directly to Vcca all the time?

Thank you for your prompt help

Yarn

over 8 years ago

0 Clemens Ladisch over 8 years ago

Guru 316860 points

If the translator is enabled while the supply voltage is still below the minimum (from the recommended operating conditions), then correct operation is not guaranteed. This means that the output value might be wrong, or that the output switches randomly (because some internal voltage crosses some threshold).

The highlighted text states that the intent is to "ensure the high-impedance state"; if you do not care that the device drives its outputs to some (possibly-wrong) voltages during power on, then you do not need to keep OE low.

0 Yarn Guo over 8 years ago in reply to Clemens Ladisch

TI__Intellectual 1440 points

Hi, Clemens:

Thank you for your prompt help.

Yes, we don't care the possibly wrong votlage level at the output during power up. Just want to make sure the output voltage level will not higher than Vcc during power up. Is this guaranteed?

Thank you so much!
Yarn

0 Clemens Ladisch over 8 years ago in reply to Yarn Guo

Guru 316860 points

An output cannot go higher than the VCC on its own side.

0 Emrys Maier over 8 years ago in reply to Yarn Guo

TI__Guru* 97046 points

Hey Yarn,

Yes - this is guaranteed.

0 Yarn Guo over 8 years ago in reply to Emrys Maier

TI__Intellectual 1440 points

Hi, Emrys and Clemens:

Thank you so much for your prompt help. Understand!

Best Regards
Yarn

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TXB0102: TXB0102: is OE needed to connected to ground during powering up