TXS0108E: Input spike influence

Miranda Gu

Part Number: TXS0108E

Hi team,

My customer try to use TXS0108 to translate I2C bus, 3.3V to 1.8V. But don't know why TXS0108 input signal has a voltage spike, as shown below.

From the waveform we can see that TXS0108 regarded the spike as high-voltage.

My customer are worried about the spike, could you please estimate the spike influence for TXS0108? Will it affect I2C communication?

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 316940 points

The TXS has edge accelerators, so it is to be expected that both lines are forced high.

What is interesting is that the input line then goes low again. Do you have long traces, cables, or connectors? Is there more than a plain pull-up resistor?

0 Dylan Hubbard over 4 years ago in reply to Clemens Ladisch

TI__Mastermind 45835 points

Hey Miranda,

This spike is due to a heavy capacitive loading causing issues with the internal one-shot. This is why its recommended to keep the load < 70 pF. The output still looks fine so I would assume it wouldn't affect I2C communication.

0 Miranda Gu over 4 years ago in reply to Clemens Ladisch

TI__Genius 16632 points

Hi Clemens,

I will send you the info through email.

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TXS0108E: Input spike influence