TXB0104-Q1: OE pin connected to VCCB

Lee, Sam

Part Number: TXB0104-Q1

Hello team,

A customer uses TXB0104-Q1 to translate1.8V to 5V, but the OE is connected to VCCB.

-. Is it okay?

-. The datasheet recommends that OE input circuit is supplied by VCCA. Can you explain why it recommends VCCA, rather than either VCCA or VCCB?

Thanks,

Sam Lee

over 2 years ago

+1 Clemens Ladisch over 2 years ago

Guru 243110 points

This is OK; see [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)?

The internal circuit that reads the voltage at the OE pin is supplied by VCCA. If the OE pin is connected to VCCB, and the two supplies power up at different times, then the OE value might not be what you want. See section 10 of the datasheet.

0 Lee, Sam over 2 years ago in reply to Clemens Ladisch

TI__Expert 4965 points

Hi Clemens,

Thank you for your answer.

They'll modify the OE connection at the next board. Can you just confirm if the following is okay?

Thanks,

Sam Lee

+1 Clemens Ladisch over 2 years ago in reply to Lee, Sam

Guru 243110 points

Everything looks OK. But R221 is needed only if OE is controlled by a GPIO; remove it.

(If OE is connected directly to a supply, it does not matter which one it is; it has an effect only when both supplies are powered.)

Logic

Logic forum

TXB0104-Q1: OE pin connected to VCCB