TXS0108E-Q1: VCCA on, VCCB off, OE low

Charles Sommer

Part Number: TXS0108E-Q1

Hi TI team,

I believe my question was partially answered here: https://e2e.ti.com/support/logic-group/logic/f/logic-forum/984327/txs0108e-q1-partial-power-operation?tisearch=e2e-sitesearch&keymatch=TXS0108E#

"A current will flow into the 5 V supply." What would be the maximum possible value for that current?

For reference, in power-down state, we have:

VCCA = 3.3V
VCCB = 0V
OE = 0V

Also, SCEA060 only gives current data when:

VCCA = 2.5V to 3.5V
VCCB = 2.5V
OE = ?

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 298860 points

There are no specifications for the characteristics of that diode. But a voltage difference of 3.3 V is quite large, so the current will be quite large.

TXS devices should not be used in this situation. Do you really need an auto-bidirectional translator? Is any single signal bidirectional?

0 Charles Sommer over 4 years ago in reply to Clemens Ladisch

Prodigy 81 points

Got it, thank you.
Then we must really make sure that VCCA is off, even when OE is low.

We're using the TXS devices for I2C signals.

0 Clemens Ladisch over 4 years ago in reply to Charles Sommer

Guru 298860 points

There are I²C level shifters. But they have two channels.

Logic

Logic forum

TXS0108E-Q1: VCCA on, VCCB off, OE low