TXB0104-Q1: is the TXB0104-Q1 broken in this case

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Please show the schematic.

Clemens Ladisch I added the third and forth figures

input is correct, output is stange

Hi,

I'll need to see more of your schematic in order to help you here.

Thanks!

Chad Crosby

Hi Chad Crosby 

i added she schematic 

thanks

These pull-down resistors are not allowed with the TXB; see section 8.3.5 of the datasheet.

But oscillations like this are typcially caused by long traces/cables; see section 8.3.3 of the datasheet.

A more robust solution would use a direction-controlled translator. But there is no single device that can translate three signals down and one signal and runs at 5 V, so you have to use two devices. I'd recommend SN74AHC125-Q1 or SN74LV125A-Q1 for the three 5 V to 3.3 V signals, and SN74AHCT1G125-Q1 for the 3.3 V to 5 V signal.

HI Clemens Ladisch 

you're saying These pull-down resistors are not allowed with the TXB

but TXB are not connected to pull down resistor  according to schematics 

 I am mistaken?

Best  regards 

R308 and R311 are connected to the TXB. In any case, they do not cause the oscillation.

R308 and R311 are connected to PINs A3 and A4.

the issue I'm having is with A1

Hi,

A couple of questions:

• What is connected to the B1 side of the device?
• How long are the PCB traces on both the A1 & B1 sides?

Thanks!

Chad Crosby