Serial with voltage translator

[mrezan]

Hi

I've problem on my design when I use voltage translator to communicate with sensors.
Can you guys see pictures below:

1.nRF52840 using 3.3v:

1.nRF52840 using 1.8v:

Issues with spi and i2c. I use the slowest speed, 1MHz for spi and 100kHz for i2c still can't get it works.
For uart it is works fine.

For i2c I've put pull up resistor on both side. Still not works.

Any one have counter this issue?

Thanks Best Regards,

Rezan

[Dmitry]

TXB0106 has 4k output resistance in DC state, it's not indended for i2c as it can't hold enough low level with strong pull-up. You probably need something like LSF0204.

For SPI, it should work (if there are no pull-ups at any side).

[awneil]

Dmitry said:

it's not indended for i2c

Which, in fact, the TI page states:

mrezan TI have resources to help you select appropriate products:

and other manufacturers will have similar.